Merge pull request #310 from dhylands/pin_map

Add pin mapping code.

22 files changed, 1318 insertions, 230 deletions

diff --git a/py/objfun.c b/py/objfun.c
index 354d7ff9ca..7c89c47000 100644
--- a/py/objfun.c
+++ b/py/objfun.c
@@ -26,26 +26,30 @@
 // mp_obj_fun_native_t defined in obj.h
 
 STATIC void check_nargs(mp_obj_fun_native_t *self, int n_args, int n_kw) {
-    if (n_kw && !self->is_kw) {
+    rt_check_nargs(n_args, self->n_args_min, self->n_args_max, n_kw, self->is_kw);
+}
+
+void rt_check_nargs(int n_args, machine_uint_t n_args_min, machine_uint_t n_args_max, int n_kw, bool is_kw) {
+    if (n_kw && !is_kw) {
         nlr_jump(mp_obj_new_exception_msg(&mp_type_TypeError,
                                           "function does not take keyword arguments"));
     }
 
-    if (self->n_args_min == self->n_args_max) {
-        if (n_args != self->n_args_min) {
+    if (n_args_min == n_args_max) {
+        if (n_args != n_args_min) {
             nlr_jump(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                                                      "function takes %d positional arguments but %d were given",
-                                                     self->n_args_min, n_args));
+                                                     n_args_min, n_args));
         }
     } else {
-        if (n_args < self->n_args_min) {
+        if (n_args < n_args_min) {
             nlr_jump(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                                                     "<fun name>() missing %d required positional arguments: <list of names of params>",
-                                                    self->n_args_min - n_args));
-        } else if (n_args > self->n_args_max) {
+                                                    n_args_min - n_args));
+        } else if (n_args > n_args_max) {
             nlr_jump(mp_obj_new_exception_msg_varg(&mp_type_TypeError,
                                                      "<fun name> expected at most %d arguments, got %d",
-                                                     self->n_args_max, n_args));
+                                                     n_args_max, n_args));
         }
     }
 }
diff --git a/py/runtime.h b/py/runtime.h
index 1eef99d2ff..7215cc8890 100644
--- a/py/runtime.h
+++ b/py/runtime.h
@@ -1,3 +1,5 @@
+void rt_check_nargs(int n_args, machine_uint_t n_args_min, machine_uint_t n_args_max, int n_kw, bool is_kw);
+
 int rt_is_true(mp_obj_t arg);
 
 mp_obj_t rt_load_const_dec(qstr qstr);
diff --git a/stm/Makefile b/stm/Makefile
index e2adddbfd9..14b690fc05 100644
--- a/stm/Makefile
+++ b/stm/Makefile
@@ -24,6 +24,9 @@ CFLAGS += -I$(STMUSBH_DIR)
 CFLAGS += -I$(FATFS_DIR)
 #CFLAGS += -I$(CC3K_DIR)
 
+BOARD ?= PYBOARD4
+CFLAGS += -Iboards/$(BOARD)
+
 #Debugging/Optimization
 ifeq ($(DEBUG), 1)
 CFLAGS += -g
@@ -68,6 +71,9 @@ SRC_C = \
 	adc.c \
 	rtc.c \
 	file.c \
+	pin.c \
+	pin_named_pins.c \
+	pin_map.c \
 #	pybwlan.c \
 
 SRC_S = \
@@ -155,6 +161,7 @@ OBJ += $(addprefix $(BUILD)/, $(SRC_STMUSBD:.c=.o))
 #OBJ += $(addprefix $(BUILD)/, $(SRC_STMUSBH:.c=.o))
 OBJ += $(addprefix $(BUILD)/, $(SRC_FATFS:.c=.o))
 #OBJ += $(addprefix $(BUILD)/, $(SRC_CC3K:.c=.o))
+OBJ += $(BUILD)/pins_$(BOARD).o
 
 all: $(BUILD)/flash.dfu
 
@@ -173,4 +180,16 @@ $(BUILD)/flash.elf: $(OBJ)
 	$(Q)$(LD) $(LDFLAGS) -o $@ $(OBJ) $(LIBS)
 	$(Q)$(SIZE) $@
 
+MAKE_PINS = boards/make-pins.py
+BOARD_PINS = boards/$(BOARD)/pins.csv
+AF_FILE = boards/stm32f4xx-af.csv
+PREFIX_FILE = boards/stm32f4xx-prefix.c
+
+$(BUILD)/pins_$(BOARD).c: $(MAKE_PINS) $(BOARD_PINS) $(AF_FILE) $(PREFIX_FILE)
+	$(ECHO) "Create $@"
+	$(Q)python $(MAKE_PINS) --board $(BOARD_PINS) --af $(AF_FILE) --prefix $(PREFIX_FILE) > $@
+
+$(BUILD)/pins_$(BOARD).o: $(BUILD)/pins_$(BOARD).c
+	$(call compile_c)
+
 include ../py/mkrules.mk
diff --git a/stm/boards/NETDUINO_PLUS_2/mpconfigboard.h b/stm/boards/NETDUINO_PLUS_2/mpconfigboard.h
new file mode 100644
index 0000000000..9c407d9cd4
--- /dev/null
+++ b/stm/boards/NETDUINO_PLUS_2/mpconfigboard.h
@@ -0,0 +1,48 @@
+#define NETDUINO_PLUS_2
+
+#define MICROPY_HW_BOARD_NAME       "NetduinoPlus2"
+
+#define MICROPY_HW_HAS_SWITCH       (1)
+
+// On the netuino, the sdcard appears to be wired up as a 1-bit
+// SPI, so the driver needs to be converted to support that before
+// we can turn this on.
+#define MICROPY_HW_HAS_SDCARD       (0)
+#define MICROPY_HW_HAS_MMA7660      (0)
+#define MICROPY_HW_HAS_LIS3DSH      (0)
+#define MICROPY_HW_HAS_LCD          (0)
+#define MICROPY_HW_HAS_WLAN         (0)
+#define MICROPY_HW_ENABLE_RNG       (1)
+#define MICROPY_HW_ENABLE_RTC       (0)
+#define MICROPY_HW_ENABLE_TIMER     (1)
+#define MICROPY_HW_ENABLE_SERVO     (1)
+#define MICROPY_HW_ENABLE_AUDIO     (0)
+
+#define USRSW_PORT          (GPIOB)
+#define USRSW_PIN           (GPIO_Pin_11)
+#define USRSW_PUPD          (GPIO_PuPd_NOPULL)
+#define USRSW_EXTI_PIN      (EXTI_PinSource11)
+#define USRSW_EXTI_PORT     (EXTI_PortSourceGPIOB)
+#define USRSW_EXTI_LINE     (EXTI_Line11)
+#define USRSW_EXTI_IRQN     (EXTI15_10_IRQn)
+#define USRSW_EXTI_EDGE     (EXTI_Trigger_Rising)
+
+/* LED */
+#define PYB_LED1_PORT   (GPIOA)         // Blue LED
+#define PYB_LED1_PIN    (GPIO_Pin_10)
+
+#define PYB_LED2_PORT   (GPIOC)         // White LED (aka Power)
+#define PYB_LED2_PIN    (GPIO_Pin_13)
+
+#define PYB_LED3_PORT   (GPIOA)         // Same as Led(1)
+#define PYB_LED3_PIN    (GPIO_Pin_10)
+
+#define PYB_LED4_PORT   (GPIOC)         // Same as Led(2)
+#define PYB_LED4_PIN    (GPIO_Pin_13)
+
+#define PYB_OTYPE       (GPIO_OType_PP)
+
+#define PYB_LED_ON(port, pin)  (port->BSRRL = pin)
+#define PYB_LED_OFF(port, pin) (port->BSRRH = pin)
+
+#define HSE_VALUE (25000000)
diff --git a/stm/boards/NETDUINO_PLUS_2/pins.csv b/stm/boards/NETDUINO_PLUS_2/pins.csv
new file mode 100644
index 0000000000..f9b94a6c87
--- /dev/null
+++ b/stm/boards/NETDUINO_PLUS_2/pins.csv
@@ -0,0 +1,28 @@
+D0,PC7
+D1,PC6
+D2,PA3
+D3,PA2
+D4,PB12
+D5,PB8
+D6,PB9
+D7,PA1
+D8,PA0
+D9,PA6
+D10,PB10
+D11,PB15
+D12,PB14
+D13,PB13
+A0,PC0
+A1,PC1
+A2,PC2
+A3,PC3
+A4,PC4
+A5,PC5
+LED,PA10
+SW,PB11
+PWR_LED,PC13
+PWR_SD,PB1
+PWR_HDR,PB2
+PWR_ETH,PC15
+RST_ETH,PD2
+
diff --git a/stm/boards/PYBOARD3/mpconfigboard.h b/stm/boards/PYBOARD3/mpconfigboard.h
new file mode 100644
index 0000000000..1632445741
--- /dev/null
+++ b/stm/boards/PYBOARD3/mpconfigboard.h
@@ -0,0 +1,42 @@
+#define PYBOARD3
+
+#define MICROPY_HW_BOARD_NAME       "PYBv3"
+
+#define MICROPY_HW_HAS_SWITCH       (1)
+#define MICROPY_HW_HAS_SDCARD       (1)
+#define MICROPY_HW_HAS_MMA7660      (1)
+#define MICROPY_HW_HAS_LIS3DSH      (0)
+#define MICROPY_HW_HAS_LCD          (0)
+#define MICROPY_HW_HAS_WLAN         (0)
+#define MICROPY_HW_ENABLE_RNG       (1)
+#define MICROPY_HW_ENABLE_RTC       (1)
+#define MICROPY_HW_ENABLE_TIMER     (1)
+#define MICROPY_HW_ENABLE_SERVO     (1)
+#define MICROPY_HW_ENABLE_AUDIO     (0)
+
+#define USRSW_PORT          (GPIOA)
+#define USRSW_PIN           (GPIO_Pin_13)
+#define USRSW_PUPD          (GPIO_PuPd_UP)
+#define USRSW_EXTI_PIN      (EXTI_PinSource13)
+#define USRSW_EXTI_PORT     (EXTI_PortSourceGPIOA)
+#define USRSW_EXTI_LINE     (EXTI_Line13)
+#define USRSW_EXTI_IRQN     (EXTI15_10_IRQn)
+#define USRSW_EXTI_EDGE     (EXTI_Trigger_Rising)
+
+/* LED */
+#define PYB_LED1_PORT   (GPIOA)
+#define PYB_LED1_PIN    (GPIO_Pin_8)
+
+#define PYB_LED2_PORT   (GPIOA)
+#define PYB_LED2_PIN    (GPIO_Pin_10)
+
+#define PYB_LED3_PORT   (GPIOC)
+#define PYB_LED3_PIN    (GPIO_Pin_4)
+
+#define PYB_LED4_PORT   (GPIOC)
+#define PYB_LED4_PIN    (GPIO_Pin_5)
+
+#define PYB_OTYPE       (GPIO_OType_OD)
+
+#define PYB_LED_ON(port, pin)  (port->BSRRH = pin)
+#define PYB_LED_OFF(port, pin) (port->BSRRL = pin)
diff --git a/stm/boards/PYBOARD3/pins.csv b/stm/boards/PYBOARD3/pins.csv
new file mode 100644
index 0000000000..cc07b15445
--- /dev/null
+++ b/stm/boards/PYBOARD3/pins.csv
@@ -0,0 +1,37 @@
+B13,PB13
+B14,PB14
+B15,PB15
+C6,PC6
+C7,PC7
+A13,PA13
+A14,PA14
+A15,PA15
+B3,PB3
+B4,PB4
+B6,PB6
+B7,PB7
+B8,PB8
+B9,PB9
+C0,PC0
+C1,PC1
+C2,PC2
+C3,PC3
+A0,PA0
+A1,PA1
+A2,PA2
+A3,PA3
+A4,PA4
+A5,PA5
+A6,PA6
+A7,PA7
+B0,PB0
+B1,PB1
+B10,PB10
+B11,PB11
+B12,PB12
+LED_R1,PA8
+LED_R2,PA10
+LED_G1,PC4
+LED_G2,PC5
+SW,PA13
+
diff --git a/stm/boards/PYBOARD4/mpconfigboard.h b/stm/boards/PYBOARD4/mpconfigboard.h
new file mode 100644
index 0000000000..3cb00b4027
--- /dev/null
+++ b/stm/boards/PYBOARD4/mpconfigboard.h
@@ -0,0 +1,42 @@
+#define PYBOARD4
+
+#define MICROPY_HW_BOARD_NAME       "PYBv4"
+
+#define MICROPY_HW_HAS_SWITCH       (1)
+#define MICROPY_HW_HAS_SDCARD       (1)
+#define MICROPY_HW_HAS_MMA7660      (1)
+#define MICROPY_HW_HAS_LIS3DSH      (0)
+#define MICROPY_HW_HAS_LCD          (1)
+#define MICROPY_HW_HAS_WLAN         (0)
+#define MICROPY_HW_ENABLE_RNG       (1)
+#define MICROPY_HW_ENABLE_RTC       (1)
+#define MICROPY_HW_ENABLE_TIMER     (1)
+#define MICROPY_HW_ENABLE_SERVO     (1)
+#define MICROPY_HW_ENABLE_AUDIO     (0)
+
+#define USRSW_PORT          (GPIOB)
+#define USRSW_PIN           (GPIO_Pin_3)
+#define USRSW_PUPD          (GPIO_PuPd_UP)
+#define USRSW_EXTI_PIN      (EXTI_PinSource3)
+#define USRSW_EXTI_PORT     (EXTI_PortSourceGPIOB)
+#define USRSW_EXTI_LINE     (EXTI_Line3)
+#define USRSW_EXTI_IRQN     (EXTI3_IRQn)
+#define USRSW_EXTI_EDGE     (EXTI_Trigger_Rising)
+
+/* LED */
+#define PYB_LED1_PORT   (GPIOA)
+#define PYB_LED1_PIN    (GPIO_Pin_13)
+
+#define PYB_LED2_PORT   (GPIOA)
+#define PYB_LED2_PIN    (GPIO_Pin_14)
+
+#define PYB_LED3_PORT   (GPIOA)
+#define PYB_LED3_PIN    (GPIO_Pin_15)
+
+#define PYB_LED4_PORT   (GPIOB)
+#define PYB_LED4_PIN    (GPIO_Pin_4)
+
+#define PYB_OTYPE       (GPIO_OType_PP)
+
+#define PYB_LED_ON(port, pin)  (port->BSRRL = pin)
+#define PYB_LED_OFF(port, pin) (port->BSRRH = pin)
diff --git a/stm/boards/PYBOARD4/pins.csv b/stm/boards/PYBOARD4/pins.csv
new file mode 100644
index 0000000000..44166bf7a8
--- /dev/null
+++ b/stm/boards/PYBOARD4/pins.csv
@@ -0,0 +1,45 @@
+X1,PB6
+X2,PB7
+X3,PC4
+X4,PB5
+X5,Reset
+X6,GND
+X7,3.3V
+X8,VIN
+X9,PA0
+X10,PA1
+X11,PA2
+X12,PA3
+X13,PA4
+X14,PA5
+X15,PA6
+X16,PA7
+X17,PB3
+X18,PC13
+X19,PC0
+X20,PC1
+X21,PC2
+X22,PC3
+X23,A3.3V
+X24,AGND
+Y1,PB10
+Y2,PB11
+Y3,PB0
+Y4,PB1
+Y5,Reset
+Y6,GND
+Y7,3.3V
+Y8,VIN
+Y9,PC6
+Y10,PC7
+Y11,PB8
+Y12,PB9
+Y13,PB12
+Y14,PB13
+Y15,PB14
+Y16,PB15
+LED_BLUE,PB4
+LED_RED,PA13
+LED_GREEN,PA14
+LED_YELLOW,PA15
+SW,PB3
diff --git a/stm/boards/STM32F4DISC/mpconfigboard.h b/stm/boards/STM32F4DISC/mpconfigboard.h
new file mode 100644
index 0000000000..2708504cb0
--- /dev/null
+++ b/stm/boards/STM32F4DISC/mpconfigboard.h
@@ -0,0 +1,43 @@
+#define STM32F4DISC
+
+#define MICROPY_HW_BOARD_NAME       "F4DISC"
+
+#define MICROPY_HW_HAS_SWITCH       (1)
+#define MICROPY_HW_HAS_SDCARD       (0)
+#define MICROPY_HW_HAS_MMA7660      (0)
+#define MICROPY_HW_HAS_LIS3DSH      (1)
+#define MICROPY_HW_HAS_LCD          (0)
+#define MICROPY_HW_HAS_WLAN         (0)
+#define MICROPY_HW_ENABLE_RNG       (1)
+#define MICROPY_HW_ENABLE_RTC       (1)
+#define MICROPY_HW_ENABLE_TIMER     (1)
+#define MICROPY_HW_ENABLE_SERVO     (0)
+#define MICROPY_HW_ENABLE_AUDIO     (0)
+
+#define USRSW_PORT          (GPIOA)
+#define USRSW_PIN           (GPIO_Pin_0)
+#define USRSW_PUPD          (GPIO_PuPd_NOPULL)
+#define USRSW_EXTI_PIN      (EXTI_PinSource0)
+#define USRSW_EXTI_PORT     (EXTI_PortSourceGPIOA)
+#define USRSW_EXTI_LINE     (EXTI_Line0)
+#define USRSW_EXTI_IRQN     (EXTI0_IRQn)
+#define USRSW_EXTI_EDGE     (EXTI_Trigger_Falling)
+
+/* LED */
+#define PYB_LED1_PORT   (GPIOD)
+#define PYB_LED1_PIN    (GPIO_Pin_14)
+
+#define PYB_LED2_PORT   (GPIOD)
+#define PYB_LED2_PIN    (GPIO_Pin_12)
+
+#define PYB_LED3_PORT   (GPIOD)
+#define PYB_LED3_PIN    (GPIO_Pin_15)
+
+#define PYB_LED4_PORT   (GPIOD)
+#define PYB_LED4_PIN    (GPIO_Pin_13)
+
+#define PYB_OTYPE       (GPIO_OType_PP)
+
+#define PYB_LED_ON(port, pin)  (port->BSRRL = pin)
+#define PYB_LED_OFF(port, pin) (port->BSRRH = pin)
+
diff --git a/stm/boards/STM32F4DISC/pins.csv b/stm/boards/STM32F4DISC/pins.csv
new file mode 100644
index 0000000000..4049fef7d9
--- /dev/null
+++ b/stm/boards/STM32F4DISC/pins.csv
@@ -0,0 +1,85 @@
+PC0,PC0
+PC1,PC1
+PC2,PC2
+PC3,PC3
+PA0,PA0
+PA1,PA1
+PA2,PA2
+PA3,PA3
+PA4,PA4
+PA5,PA5
+PA6,PA6
+PA7,PA7
+PC4,PC4
+PC5,PC5
+PB0,PB0
+PB1,PB1
+PB2,PB2
+PE7,PE7
+PE8,PE8
+PE9,PE9
+PE10,PE10
+PE11,PE11
+PE12,PE12
+PE13,PE13
+PE14,PE14
+PE15,PE15
+PB10,PB10
+PB11,PB11
+PB12,PB12
+PB13,PB13
+PB14,PB14
+PB15,PB15
+PD8,PD8
+PD9,PD9
+PD10,PD10
+PD11,PD11
+PD12,PD12
+PD13,PD13
+PD14,PD14
+PD15,PD15
+PC6,PC6
+PC7,PC7
+PC8,PC8
+PC9,PC9
+PA8,PA8
+PA9,PA9
+PA10,PA10
+PA13,PA13
+PA14,PA14
+PA15,PA15
+PC10,PC10
+PC11,PC11
+PC12,PC12
+PD0,PD0
+PD1,PD1
+PD2,PD2
+PD3,PD3
+PD4,PD4
+PD5,PD5
+PD6,PD6
+PD7,PD7
+PB4,PB4
+PB5,PB5
+PB6,PB6
+PB7,PB7
+PB8,PB8
+PB9,PB9
+PE0,PE0
+PE1,PE1
+PE2,PE2
+PE3,PE3
+PE4,PE4
+PE5,PE5
+PE6,PE6
+PC13,PC13
+PC14,PC14
+PC15,PC15
+PH0,PH0
+PH1,PH1
+LED_GREEN,PD12
+LED_ORANGE,PD13
+LED_RED,PD14
+LED_BLUE,PD15
+SW,PA0
+
diff --git a/stm/boards/make-pins.py b/stm/boards/make-pins.py
new file mode 100755
index 0000000000..0bc9118b08
--- /dev/null
+++ b/stm/boards/make-pins.py
@@ -0,0 +1,241 @@
+#!/usr/bin/env python
+"""Creates the pin file for the STM32F4xx."""
+
+from __future__ import print_function
+
+import argparse
+import sys
+import csv
+
+SUPPORTED_FN = {
+    'TIM'   : ['CH1',  'CH2',  'CH3',  'CH4',
+               'CH1N', 'CH2N', 'CH3N', 'CH1_ETR', 'ETR', 'BKIN'],
+    'I2C'   : ['SDA', 'SCL'],
+    'USART' : ['RX', 'TX', 'CTS', 'RTS', 'CK'],
+    'UART'  : ['RX', 'TX', 'CTS', 'RTS'],
+    'SPI'   : ['NSS', 'SCK', 'MISO', 'MOSI']
+}
+
+def parse_port_pin(name_str):
+    """Parses a string and returns a (port-num, pin-num) tuple."""
+    if len(name_str) < 3:
+        raise ValueError("Expecting pin name to be at least 3 charcters.")
+    if name_str[0] != 'P':
+        raise ValueError("Expecting pin name to start with P")
+    if name_str[1] < 'A' or name_str[1] > 'J':
+        raise ValueError("Expecting pin port to be between A and J")
+    port = ord(name_str[1]) - ord('A')
+    pin_str = name_str[2:]
+    if not pin_str.isdigit():
+        raise ValueError("Expecting numeric pin number.")
+    return (port, int(pin_str))
+
+def split_name_num(name_num):
+    num = None
+    for num_idx in range(len(name_num) - 1, -1, -1):
+        if not name_num[num_idx].isdigit():
+            name = name_num[0:num_idx + 1]
+            num_str = name_num[num_idx + 1:]
+            if len(num_str) > 0:
+                num = int(num_str)
+            break
+    return name, num
+
+
+class AlternateFunction(object):
+    """Holds the information associated with a pins alternate function."""
+
+    def __init__(self, idx, af_str):
+        self.idx = idx
+        self.af_str = af_str
+
+        self.func = ''
+        self.fn_num = None
+        self.pin_type = ''
+        self.supported = False
+
+        af_words = af_str.split('_', 1)
+        self.func, self.fn_num = split_name_num(af_words[0])
+        if len(af_words) > 1:
+            self.pin_type = af_words[1]
+        if self.func in SUPPORTED_FN:
+            pin_types = SUPPORTED_FN[self.func]
+            if self.pin_type in pin_types:
+                self.supported = True
+
+    def is_supported(self):
+        return self.supported
+
+    def ptr(self):
+        """Returns the numbered function (i.e. USART6) for this AF."""
+        if self.fn_num is None:
+            return self.func
+        return '{:s}{:d}'.format(self.func, self.fn_num)
+
+    def print(self):
+        """Prints the C representation of this AF."""
+        if self.supported:
+            print('  AF',  end='')
+        else:
+            print('  //', end='')
+        fn_num = self.fn_num
+        if fn_num is None:
+            fn_num = 0
+        print('({:2d}, {:8s}, {:2d}, {:10s}, {:8s}), // {:s}'.format(self.idx,
+              self.func, fn_num, self.pin_type, self.ptr(), self.af_str))
+
+
+class Pin(object):
+    """Holds the information associated with a pin."""
+
+    def __init__(self, port, pin):
+        self.port = port
+        self.pin = pin
+        self.alt_fn = []
+        self.board_name = None
+        self.alt_fn_count = 0
+
+    def port_letter(self):
+        return chr(self.port + ord('A'))
+
+    def pin_name(self):
+        return '{:s}{:d}'.format(self.port_letter(), self.pin)
+
+    def parse_af(self, af_idx, af_strs_in):
+        if len(af_strs_in) == 0:
+            return
+        # If there is a slash, then the slash separates 2 aliases for the
+        # same alternate function.
+        af_strs = af_strs_in.split('/')
+        for af_str in af_strs:
+            alt_fn = AlternateFunction(af_idx, af_str)
+            self.alt_fn.append(alt_fn)
+            if alt_fn.is_supported():
+                self.alt_fn_count += 1
+
+    def alt_fn_name(self):
+        if self.alt_fn_count > 0:
+            return 'pin_{:s}_af'.format(self.pin_name())
+        return 'NULL'
+
+    def print(self):
+        if self.alt_fn_count == 0:
+            print("// ",  end='')
+        print('const pin_af_obj_t {:s}[] = {{'.format(self.alt_fn_name()))
+        for alt_fn in self.alt_fn:
+            alt_fn.print()
+        if self.alt_fn_count == 0:
+            print("// ",  end='')
+        print('};')
+        print('')
+        print('const pin_obj_t pin_{:s} = PIN({:s}, {:d}, {:d}, {:s});'.format(
+            self.pin_name(), self.port_letter(), self.pin,
+            self.alt_fn_count, self.alt_fn_name()))
+        print('')
+
+
+class Pins(object):
+
+    def __init__(self):
+        self.pins = []
+        self.board_pins = []
+
+    def find_pin(self, port_num, pin_num):
+        for pin in self.pins:
+            if pin.port == port_num and pin.pin == pin_num:
+                return pin
+
+    def parse_af_file(self, filename, pinname_col, af_col):
+        with open(filename, 'r') as csvfile:
+            rows = csv.reader(csvfile)
+            for row in rows:
+                try:
+                    (port_num, pin_num) = parse_port_pin(row[pinname_col])
+                except:
+                    continue
+                pin = Pin(port_num, pin_num)
+                for af_idx in range(af_col, len(row)):
+                    pin.parse_af(af_idx - af_col, row[af_idx])
+                self.pins.append(pin)
+
+    def parse_board_file(self, filename):
+        with open(filename, 'r') as csvfile:
+            rows = csv.reader(csvfile)
+            for row in rows:
+                try:
+                    (port_num, pin_num) = parse_port_pin(row[1])
+                except:
+                    continue
+                pin = self.find_pin(port_num, pin_num)
+                if pin:
+                    pin.board_name = row[0]
+                    self.board_pins.append(pin)
+
+    def print_named(self, label, pins):
+        print('const pin_named_pin_t pin_{:s}_pins[] = {{'.format(label))
+        for pin in pins:
+            if pin.board_name:
+                if label == 'board':
+                    pin_name = pin.board_name
+                else:
+                    pin_name = pin.pin_name()
+                print('  {{ "{:s}", &pin_{:s} }},'.format(pin_name,  pin.pin_name()))
+        print('  { NULL, NULL }')
+        print('};')
+
+    def print(self):
+        for pin in self.pins:
+            if pin.board_name:
+                pin.print()
+        self.print_named('cpu', self.pins)
+        print('')
+        self.print_named('board', self.board_pins)
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        prog="make-pins.py",
+        usage="%(prog)s [options] [command]",
+        description="Generate board specific pin file"
+    )
+    parser.add_argument(
+        "-a", "--af",
+        dest="af_filename",
+        help="Specifies the alternate function file for the chip",
+        default="stm32f4xx-af.csv"
+    )
+    parser.add_argument(
+        "-b", "--board",
+        dest="board_filename",
+        help="Specifies the board file",
+    )
+    parser.add_argument(
+        "-p", "--prefix",
+        dest="prefix_filename",
+        help="Specifies beginning portion of generated pins file",
+        default="stm32f4xx-prefix.c"
+    )
+    args = parser.parse_args(sys.argv[1:])
+
+    pins = Pins()
+
+    print('// This file was automatically generated by make-pins.py')
+    print('//')
+    if args.af_filename:
+        print('// --af {:s}'.format(args.af_filename))
+        pins.parse_af_file(args.af_filename, 1, 2)
+
+    if args.board_filename:
+        print('// --board {:s}'.format(args.board_filename))
+        pins.parse_board_file(args.board_filename)
+
+    if args.prefix_filename:
+        print('// --prefix {:s}'.format(args.prefix_filename))
+        print('')
+        with open(args.prefix_filename, 'r') as prefix_file:
+            print(prefix_file.read())
+    pins.print()
+
+
+if __name__ == "__main__":
+    main()
diff --git a/stm/boards/stm32f4xx-af.csv b/stm/boards/stm32f4xx-af.csv
new file mode 100644
index 0000000000..fde7fcfc11
--- /dev/null
+++ b/stm/boards/stm32f4xx-af.csv
@@ -0,0 +1,142 @@
+Port,,AF0,AF1,AF2,AF3,AF4,AF5,AF6,AF7,AF8,AF9,AF10,AF11,AF12,AF13,AF14,AF15
+,,SYS,TIM1/2,TIM3/4/5,TIM8/9/10/11,I2C1/2/3,SPI1/SPI2/I2S2/I2S2ext,SPI3/I2Sext/I2S3,USART1/2/3/I2S3ext,UART4/5/USART6,CAN1/CAN2/TIM12/13/14,OTG_FS/OTG_HS,ETH,FSMC/SDIO/OTG_FS,DCMI,,
+PortA,PA0,,TIM2_CH1_ETR,TIM5_CH1,TIM8_ETR,,,,USART2_CTS,UART4_TX,,,ETH_MII_CRS,,,,EVENTOUT
+PortA,PA1,,TIM2_CH2,TIM5_CH2,,,,,USART2_RTS,UART4_RX,,,ETH_MII_RX_CLK/ETH_RMII__REF_CLK,,,,EVENTOUT
+PortA,PA2,,TIM2_CH3,TIM5_CH3,TIM9_CH1,,,,USART2_TX,,,,ETH_MDIO,,,,EVENTOUT
+PortA,PA3,,TIM2_CH4,TIM5_CH4,TIM9_CH2,,,,USART2_RX,,,OTG_HS_ULPI_D0,ETH_MII_COL,,,,EVENTOUT
+PortA,PA4,,,,,,SPI1_NSS,SPI3_NSS/I2S3_WS,USART2_CK,,,,,OTG_HS_SOF,DCMI_HSYNC,,EVENTOUT
+PortA,PA5,,TIM2_CH1_ETR,,TIM8_CH1N,,SPI1_SCK,,,,,OTG_HS_ULPI_CK,,,,,EVENTOUT
+PortA,PA6,,TIM1_BKIN,TIM3_CH1,TIM8_BKIN,,SPI1_MISO,,,,TIM13_CH1,,,,DCMI_PIXCK,,EVENTOUT
+PortA,PA7,,TIM1_CH1N,TIM3_CH2,TIM8_CH1N,,SPI1_MOSI,,,,TIM14_CH1,,ETH_MII_RX_DV/ETH_RMII_CRS_DV,,,,EVENTOUT
+PortA,PA8,MCO1,TIM1_CH1,,,I2C3_SCL,,,USART1_CK,,,OTG_FS_SOF,,,,,EVENTOUT
+PortA,PA9,,TIM1_CH2,,,I2C3_SMBA,,,USART1_TX,,,,,,DCMI_D0,,EVENTOUT
+PortA,PA10,,TIM1_CH3,,,,,,USART1_RX,,,OTG_FS_ID,,,DCMI_D1,,EVENTOUT
+PortA,PA11,,TIM1_CH4,,,,,,USART1_CTS,,CAN1_RX,OTG_FS_DM,,,,,EVENTOUT
+PortA,PA12,,TIM1_ETR,,,,,,USART1_RTS,,CAN1_TX,OTG_FS_DP,,,,,EVENTOUT
+PortA,PA13,JTMS-SWDIO,,,,,,,,,,,,,,,EVENTOUT
+PortA,PA14,JTCK-SWCLK,,,,,,,,,,,,,,,EVENTOUT
+PortA,PA15,JTDI,TIM2_CH1/TIM2_ETR,,,,SPI1_NSS,SPI3_NSS/I2S3_WS,,,,,,,,,EVENTOUT
+PortB,PB0,,TIM1_CH2N,TIM3_CH3,TIM8_CH2N,,,,,,,OTG_HS_ULPI_D1,ETH_MII_RXD2,,,,EVENTOUT
+PortB,PB1,,TIM1_CH3N,TIM3_CH4,TIM8_CH3N,,,,,,,OTG_HS_ULPI_D2,ETH_MII_RXD3,,,,EVENTOUT
+PortB,PB2,,,,,,,,,,,,,,,,EVENTOUT
+PortB,PB3,JTDO/TRACESWO,TIM2_CH2,,,,SPI1_SCK,SPI3_SCKI2S3_CK,,,,,,,,,EVENTOUT
+PortB,PB4,NJTRST,,TIM3_CH1,,,SPI1_MISO,SPI3_MISO,I2S3ext_SD,,,,,,,,EVENTOUT
+PortB,PB5,,,TIM3_CH2,,I2C1_SMBA,SPI1_MOSI,SPI3_MOSI/I2S3_SD,,,CAN2_RX,OTG_HS_ULPI_D7,ETH_PPS_OUT,,DCMI_D10,,EVENTOUT
+PortB,PB6,,,TIM4_CH1,,I2C1_SCL,,,USART1_TX,,CAN2_TX,,,,DCMI_D5,,EVENTOUT
+PortB,PB7,,,TIM4_CH2,,I2C1_SDA,,,USART1_RX,,,,,FSMC_NL,DCMI_VSYNC,,EVENTOUT
+PortB,PB8,,,TIM4_CH3,TIM10_CH1,I2C1_SCL,,,,,CAN1_RX,,ETH_MII_TXD3,SDIO_D4,DCMI_D6,,EVENTOUT
+PortB,PB9,,,TIM4_CH4,TIM11_CH1,I2C1_SDA,SPI2_NSS/I2S2_WS,,,,CAN1_TX,,,SDIO_D5,DCMI_D7,,EVENTOUT
+PortB,PB10,,TIM2_CH3,,,I2C2_SCL,SPI2_SCKI2S2_CK,,USART3_TX,,,OTG_HS_ULPI_D3,ETH_MII_RX_ER,,,,EVENTOUT
+PortB,PB11,,TIM2_CH4,,,I2C2_SDA,,,USART3_RX,,,OTG_HS_ULPI_D4,ETH_MII_TX_EN/ETH_RMII_TX_EN,,,,EVENTOUT
+PortB,PB12,,TIM1_BKIN,,,I2C2_SMBA,SPI2_NSS/I2S2_WS,,USART3_CK,,CAN2_RX,OTG_HS_ULPI_D5,ETH_MII_TXD0/ETH_RMII_TXD0,OTG_HS_ID,,,EVENTOUT
+PortB,PB13,,TIM1_CH1N,,,,SPI2_SCKI2S2_CK,,USART3_CTS,,CAN2_TX,OTG_HS_ULPI_D6,ETH_MII_TXD1/ETH_RMII_TXD1,,,,EVENTOUT
+PortB,PB14,,TIM1_CH2N,,TIM8_CH2N,,SPI2_MISO,I2S2ext_SD,USART3_RTS,,TIM12_CH1,,,OTG_HS_DM,,,EVENTOUT
+PortB,PB15,RTC_REFIN,TIM1_CH3N,,TIM8_CH3N,,SPI2_MOSI/I2S2_SD,,,,TIM12_CH2,,,OTG_HS_DP,,,EVENTOUT
+PortC,PC0,,,,,,,,,,,OTG_HS_ULPI_STP,,,,,EVENTOUT
+PortC,PC1,,,,,,,,,,,,ETH_MDC,,,,EVENTOUT
+PortC,PC2,,,,,,SPI2_MISO,I2S2ext_SD,,,,OTG_HS_ULPI_DIR,ETH_MII_TXD2,,,,EVENTOUT
+PortC,PC3,,,,,,SPI2_MOSI/I2S2_SD,,,,,OTG_HS_ULPI_NXT,ETH_MII_TX_CLK,,,,EVENTOUT
+PortC,PC4,,,,,,,,,,,,ETH_MII_RXD0/ETH_RMII_RXD0,,,,EVENTOUT
+PortC,PC5,,,,,,,,,,,,ETH_MII_RXD1/ETH_RMII_RXD1,,,,EVENTOUT
+PortC,PC6,,,TIM3_CH1,TIM8_CH1,,I2S2_MCK,,,USART6_TX,,,,SDIO_D6,DCMI_D0,,EVENTOUT
+PortC,PC7,,,TIM3_CH2,TIM8_CH2,,,I2S3_MCK,,USART6_RX,,,,SDIO_D7,DCMI_D1,,EVENTOUT
+PortC,PC8,,,TIM3_CH3,TIM8_CH3,,,,,USART6_CK,,,,SDIO_D0,DCMI_D2,,EVENTOUT
+PortC,PC9,MCO2,,TIM3_CH4,TIM8_CH4,I2C3_SDA,I2S_CKIN,,,,,,,SDIO_D1,DCMI_D3,,EVENTOUT
+PortC,PC10,,,,,,,SPI3_SCK/I2S3_CK,USART3_TX,UART4_TX,,,,SDIO_D2,DCMI_D8,,EVENTOUT
+PortC,PC11,,,,,,I2S3ext_SD,SPI3_MISO,USART3_RX,UART4_RX,,,,SDIO_D3,DCMI_D4,,EVENTOUT
+PortC,PC12,,,,,,,SPI3_MOSI/I2S3_SD,USART3_CK,UART5_TX,,,,SDIO_CK,DCMI_D9,,EVENTOUT
+PortC,PC13,,,,,,,,,,,,,,,,EVENTOUT
+PortC,PC14,,,,,,,,,,,,,,,,EVENTOUT
+PortC,PC15,,,,,,,,,,,,,,,,EVENTOUT
+PortD,PD0,,,,,,,,,,CAN1_RX,,,FSMC_D2,,,EVENTOUT
+PortD,PD1,,,,,,,,,,CAN1_TX,,,FSMC_D3,,,EVENTOUT
+PortD,PD2,,,TIM3_ETR,,,,,,UART5_RX,,,,SDIO_CMD,DCMI_D11,,EVENTOUT
+PortD,PD3,,,,,,,,USART2_CTS,,,,,FSMC_CLK,,,EVENTOUT
+PortD,PD4,,,,,,,,USART2_RTS,,,,,FSMC_NOE,,,EVENTOUT
+PortD,PD5,,,,,,,,USART2_TX,,,,,FSMC_NWE,,,EVENTOUT
+PortD,PD6,,,,,,,,USART2_RX,,,,,FSMC_NWAIT,,,EVENTOUT
+PortD,PD7,,,,,,,,USART2_CK,,,,,FSMC_NE1/FSMC_NCE2,,,EVENTOUT
+PortD,PD8,,,,,,,,USART3_TX,,,,,FSMC_D13,,,EVENTOUT
+PortD,PD9,,,,,,,,USART3_RX,,,,,FSMC_D14,,,EVENTOUT
+PortD,PD10,,,,,,,,USART3_CK,,,,,FSMC_D15,,,EVENTOUT
+PortD,PD11,,,,,,,,USART3_CTS,,,,,FSMC_A16,,,EVENTOUT
+PortD,PD12,,,TIM4_CH1,,,,,USART3_RTS,,,,,FSMC_A17,,,EVENTOUT
+PortD,PD13,,,TIM4_CH2,,,,,,,,,,FSMC_A18,,,EVENTOUT
+PortD,PD14,,,TIM4_CH3,,,,,,,,,,FSMC_D0,,,EVENTOUT
+PortD,PD15,,,TIM4_CH4,,,,,,,,,,FSMC_D1,,,EVENTOUT
+PortE,PE0,,,TIM4_ETR,,,,,,,,,,FSMC_NBL0,DCMI_D2,,EVENTOUT
+PortE,PE1,,,,,,,,,,,,,FSMC_NBL1,DCMI_D3,,EVENTOUT
+PortE,PE2,TRACECLK,,,,,,,,,,,ETH_MII_TXD3,FSMC_A23,,,EVENTOUT
+PortE,PE3,TRACED0,,,,,,,,,,,,FSMC_A19,,,EVENTOUT
+PortE,PE4,TRACED1,,,,,,,,,,,,FSMC_A20,DCMI_D4,,EVENTOUT
+PortE,PE5,TRACED2,,,TIM9_CH1,,,,,,,,,FSMC_A21,DCMI_D6,,EVENTOUT
+PortE,PE6,TRACED3,,,TIM9_CH2,,,,,,,,,FSMC_A22,DCMI_D7,,EVENTOUT
+PortE,PE7,,TIM1_ETR,,,,,,,,,,,FSMC_D4,,,EVENTOUT
+PortE,PE8,,TIM1_CH1N,,,,,,,,,,,FSMC_D5,,,EVENTOUT
+PortE,PE9,,TIM1_CH1,,,,,,,,,,,FSMC_D6,,,EVENTOUT
+PortE,PE10,,TIM1_CH2N,,,,,,,,,,,FSMC_D7,,,EVENTOUT
+PortE,PE11,,TIM1_CH2,,,,,,,,,,,FSMC_D8,,,EVENTOUT
+PortE,PE12,,TIM1_CH3N,,,,,,,,,,,FSMC_D9,,,EVENTOUT
+PortE,PE13,,TIM1_CH3,,,,,,,,,,,FSMC_D10,,,EVENTOUT
+PortE,PE14,,TIM1_CH4,,,,,,,,,,,FSMC_D11,,,EVENTOUT
+PortE,PE15,,TIM1_BKIN,,,,,,,,,,,FSMC_D12,,,EVENTOUT
+PortF,PF0,,,,,I2C2_SDA,,,,,,,,FSMC_A0,,,EVENTOUT
+PortF,PF1,,,,,I2C2_SCL,,,,,,,,FSMC_A1,,,EVENTOUT
+PortF,PF2,,,,,I2C2_SMBA,,,,,,,,FSMC_A2,,,EVENTOUT
+PortF,PF3,,,,,,,,,,,,,FSMC_A3,,,EVENTOUT
+PortF,PF4,,,,,,,,,,,,,FSMC_A4,,,EVENTOUT
+PortF,PF5,,,,,,,,,,,,,FSMC_A5,,,EVENTOUT
+PortF,PF6,,,,TIM10_CH1,,,,,,,,,FSMC_NIORD,,,EVENTOUT
+PortF,PF7,,,,TIM11_CH1,,,,,,,,,FSMC_NREG,,,EVENTOUT
+PortF,PF8,,,,,,,,,,TIM13_CH1,,,FSMC_NIOWR,,,EVENTOUT
+PortF,PF9,,,,,,,,,,TIM14_CH1,,,FSMC_CD,,,EVENTOUT
+PortF,PF10,,,,,,,,,,,,,FSMC_INTR,,,EVENTOUT
+PortF,PF11,,,,,,,,,,,,,,DCMI_D12,,EVENTOUT
+PortF,PF12,,,,,,,,,,,,,FSMC_A6,,,EVENTOUT
+PortF,PF13,,,,,,,,,,,,,FSMC_A7,,,EVENTOUT
+PortF,PF14,,,,,,,,,,,,,FSMC_A8,,,EVENTOUT
+PortF,PF15,,,,,,,,,,,,,FSMC_A9,,,EVENTOUT
+PortG,PG0,,,,,,,,,,,,,FSMC_A10,,,EVENTOUT
+PortG,PG1,,,,,,,,,,,,,FSMC_A11,,,EVENTOUT
+PortG,PG2,,,,,,,,,,,,,FSMC_A12,,,EVENTOUT
+PortG,PG3,,,,,,,,,,,,,FSMC_A13,,,EVENTOUT
+PortG,PG4,,,,,,,,,,,,,FSMC_A14,,,EVENTOUT
+PortG,PG5,,,,,,,,,,,,,FSMC_A15,,,EVENTOUT
+PortG,PG6,,,,,,,,,,,,,FSMC_INT2,,,EVENTOUT
+PortG,PG7,,,,,,,,,USART6_CK,,,,FSMC_INT3,,,EVENTOUT
+PortG,PG8,,,,,,,,,USART6_RTS,,,ETH_PPS_OUT,,,,EVENTOUT
+PortG,PG9,,,,,,,,,USART6_RX,,,,FSMC_NE2/FSMC_NCE3,,,EVENTOUT
+PortG,PG10,,,,,,,,,,,,,FSMC_NCE4_1/FSMC_NE3,,,EVENTOUT
+PortG,PG11,,,,,,,,,,,,ETH_MII_TX_EN/ETH_RMII_TX_EN,FSMC_NCE4_2,,,EVENTOUT
+PortG,PG12,,,,,,,,,USART6_RTS,,,,FSMC_NE4,,,EVENTOUT
+PortG,PG13,,,,,,,,,USART6_CTS,,,ETH_MII_TXD0/ETH_RMII_TXD0,FSMC_A24,,,EVENTOUT
+PortG,PG14,,,,,,,,,USART6_TX,,,ETH_MII_TXD1/ETH_RMII_TXD1,FSMC_A25,,,EVENTOUT
+PortG,PG15,,,,,,,,,USART6_CTS,,,,,DCMI_D13,,EVENTOUT
+PortH,PH0,,,,,,,,,,,,,,,,EVENTOUT
+PortH,PH1,,,,,,,,,,,,,,,,EVENTOUT
+PortH,PH2,,,,,,,,,,,,ETH_MII_CRS,,,,EVENTOUT
+PortH,PH3,,,,,,,,,,,,ETH_MII_COL,,,,EVENTOUT
+PortH,PH4,,,,,I2C2_SCL,,,,,,OTG_HS_ULPI_NXT,,,,,EVENTOUT
+PortH,PH5,,,,,I2C2_SDA,,,,,,,,,,,EVENTOUT
+PortH,PH6,,,,,I2C2_SMBA,,,,,TIM12_CH1,,ETH_MII_RXD2,,,,EVENTOUT
+PortH,PH7,,,,,I2C3_SCL,,,,,,,ETH_MII_RXD3,,,,EVENTOUT
+PortH,PH8,,,,,I2C3_SDA,,,,,,,,,DCMI_HSYNC,,EVENTOUT
+PortH,PH9,,,,,I2C3_SMBA,,,,,TIM12_CH2,,,,DCMI_D0,,EVENTOUT
+PortH,PH10,,,TIM5_CH1,,,,,,,,,,,DCMI_D1,,EVENTOUT
+PortH,PH11,,,TIM5_CH2,,,,,,,,,,,DCMI_D2,,EVENTOUT
+PortH,PH12,,,TIM5_CH3,,,,,,,,,,,DCMI_D3,,EVENTOUT
+PortH,PH13,,,,TIM8_CH1N,,,,,,CAN1_TX,,,,,,EVENTOUT
+PortH,PH14,,,,TIM8_CH2N,,,,,,,,,,DCMI_D4,,EVENTOUT
+PortH,PH15,,,,TIM8_CH3N,,,,,,,,,,DCMI_D11,,EVENTOUT
+PortI,PI0,,,TIM5_CH4,,,SPI2_NSS/I2S2_WS,,,,,,,,DCMI_D13,,EVENTOUT
+PortI,PI1,,,,,,SPI2_SCKI2S2_CK,,,,,,,,DCMI_D8,,EVENTOUT
+PortI,PI2,,,,TIM8_CH4,,SPI2_MISO,I2S2ext_SD,,,,,,,DCMI_D9,,EVENTOUT
+PortI,PI3,,,,TIM8_ETR,,SPI2_MOSI/I2S2_SD,,,,,,,,DCMI_D10,,EVENTOUT
+PortI,PI4,,,,TIM8_BKIN,,,,,,,,,,DCMI_D5,,EVENTOUT
+PortI,PI5,,,,TIM8_CH1,,,,,,,,,,DCMI_VSYNC,,EVENTOUT
+PortI,PI6,,,,TIM8_CH2,,,,,,,,,,DCMI_D6,,EVENTOUT
+PortI,PI7,,,,TIM8_CH3,,,,,,,,,,DCMI_D7,,EVENTOUT
+PortI,PI8,,,,,,,,,,,,,,,,EVENTOUT
+PortI,PI9,,,,,,,,,,CAN1_RX,,,,,,EVENTOUT
+PortI,PI10,,,,,,,,,,,,ETH_MII_RX_ER,,,,EVENTOUT
+PortI,PI11,,,,,,,,,,,OTG_HS_ULPI_DIR,,,,,EVENTOUT
diff --git a/stm/boards/stm32f4xx-prefix.c b/stm/boards/stm32f4xx-prefix.c
new file mode 100644
index 0000000000..e68de4cf4e
--- /dev/null
+++ b/stm/boards/stm32f4xx-prefix.c
@@ -0,0 +1,34 @@
+// stm32fxx-prefix.c becomes the initial portion of the generated pins file.
+
+#include <stdio.h>
+#include <stdint.h>
+#include <stm32f4xx.h>
+
+#include "misc.h"
+#include "mpconfig.h"
+#include "qstr.h"
+#include "obj.h"
+
+#include "pin.h"
+
+#define AF(af_idx, af_fn, af_unit, af_type, af_ptr) \
+{ \
+    { &pin_af_obj_type }, \
+    .idx = (af_idx), \
+    .fn = AF_FN_ ## af_fn, \
+    .unit = (af_unit), \
+    .type = AF_PIN_TYPE_ ## af_fn ## _ ## af_type, \
+    .af_fn = (af_ptr) \
+}
+
+#define PIN(p_port, p_pin, p_num_af, p_af) \
+{ \
+    { &pin_obj_type }, \
+    .name = #p_port #p_pin, \
+    .port = PORT_ ## p_port, \
+    .pin = (p_pin), \
+    .num_af = (p_num_af), \
+    .pin_mask = (1 << ((p_pin) & 0x0f)), \
+    .gpio = GPIO ## p_port, \
+    .af = p_af, \
+}
diff --git a/stm/gpio.c b/stm/gpio.c
index 99fb49be4f..e3db4086e7 100644
--- a/stm/gpio.c
+++ b/stm/gpio.c
@@ -28,43 +28,18 @@
 #include "runtime.h"
 #include "systick.h"
 #include "gpio.h"
-
-void parse_pin_name(mp_obj_t name, GPIO_TypeDef **port, uint *pin) {
-    const char *pin_name = mp_obj_str_get_str(name);
-    switch (pin_name[0]) {
-        case 'A': case 'a': *port = GPIOA; break;
-        case 'B': case 'b': *port = GPIOB; break;
-        case 'C': case 'c': *port = GPIOC; break;
-        case 'D': case 'd': *port = GPIOD; break;
-        default: goto pin_error;
-    }
-    *pin = 0;
-    for (const char *s = pin_name + 1; *s; s++) {
-        if (!('0' <= *s && *s <= '9')) {
-            goto pin_error;
-        }
-        *pin = 10 * (*pin) + *s - '0';
-    }
-    if (!(0 <= *pin && *pin <= 15)) {
-        goto pin_error;
-    }
-
-    return;
-
-pin_error:
-    nlr_jump(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "pin %s does not exist", pin_name));
-}
+#include "pin.h"
 
 mp_obj_t pyb_gpio(uint n_args, mp_obj_t *args) {
     //assert(1 <= n_args && n_args <= 2);
 
-    GPIO_TypeDef *port;
-    uint pin;
-    parse_pin_name(args[0], &port, &pin);
+    const pin_obj_t *pin = pin_map_user_obj(args[0]);
+    GPIO_TypeDef *port = pin->gpio;
+    uint16_t pin_mask = pin->pin_mask;
 
     if (n_args == 1) {
         // get pin
-        if ((port->IDR & (1 << pin)) != (uint32_t)Bit_RESET) {
+        if ((port->IDR & pin_mask) != (uint32_t)Bit_RESET) {
             return MP_OBJ_NEW_SMALL_INT(1);
         } else {
             return MP_OBJ_NEW_SMALL_INT(0);
@@ -73,10 +48,10 @@ mp_obj_t pyb_gpio(uint n_args, mp_obj_t *args) {
         // set pin
         if (rt_is_true(args[1])) {
             // set pin high
-            port->BSRRL = 1 << pin;
+            port->BSRRL = pin_mask;
         } else {
             // set pin low
-            port->BSRRH = 1 << pin;
+            port->BSRRH = pin_mask;
         }
         return mp_const_none;
     }
@@ -84,13 +59,13 @@ mp_obj_t pyb_gpio(uint n_args, mp_obj_t *args) {
 
 MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pyb_gpio_obj, 1, 2, pyb_gpio);
 
-mp_obj_t pyb_gpio_input(mp_obj_t arg_port_pin, mp_obj_t arg_mode) {
-    GPIO_TypeDef *port;
-    uint pin;
-    parse_pin_name(arg_port_pin, &port, &pin);
+mp_obj_t pyb_gpio_input(mp_obj_t arg_pin, mp_obj_t arg_mode) {
+    const pin_obj_t *pin = pin_map_user_obj(arg_pin);
+    GPIO_TypeDef *port = pin->gpio;
+    uint16_t pin_mask = pin->pin_mask;
 
     GPIO_InitTypeDef GPIO_InitStructure;
-    GPIO_InitStructure.GPIO_Pin = 1 << pin;
+    GPIO_InitStructure.GPIO_Pin = pin_mask;
     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_IN;
     GPIO_InitStructure.GPIO_PuPd = mp_obj_get_int(arg_mode);
     GPIO_Init(port, &GPIO_InitStructure);
@@ -100,13 +75,13 @@ mp_obj_t pyb_gpio_input(mp_obj_t arg_port_pin, mp_obj_t arg_mode) {
 
 MP_DEFINE_CONST_FUN_OBJ_2(pyb_gpio_input_obj, pyb_gpio_input);
 
-mp_obj_t pyb_gpio_output(mp_obj_t arg_port_pin, mp_obj_t arg_mode) {
-    GPIO_TypeDef *port;
-    uint pin;
-    parse_pin_name(arg_port_pin, &port, &pin);
+mp_obj_t pyb_gpio_output(mp_obj_t arg_pin, mp_obj_t arg_mode) {
+    const pin_obj_t *pin = pin_map_user_obj(arg_pin);
+    GPIO_TypeDef *port = pin->gpio;
+    uint16_t pin_mask = pin->pin_mask;
 
     GPIO_InitTypeDef GPIO_InitStructure;
-    GPIO_InitStructure.GPIO_Pin = 1 << pin;
+    GPIO_InitStructure.GPIO_Pin = pin_mask;
     GPIO_InitStructure.GPIO_Mode = GPIO_Mode_OUT;
     GPIO_InitStructure.GPIO_Speed = GPIO_Fast_Speed;
     GPIO_InitStructure.GPIO_OType = mp_obj_get_int(arg_mode);
diff --git a/stm/main.c b/stm/main.c
index ec3fb09ed6..4fed5850a6 100644
--- a/stm/main.c
+++ b/stm/main.c
@@ -50,6 +50,7 @@
 #include "adc.h"
 #include "rtc.h"
 #include "file.h"
+#include "pin.h"
 
 int errno;
 
@@ -446,6 +447,7 @@ soft_reset:
         rt_store_attr(m, MP_QSTR_ADC, (mp_obj_t)&pyb_ADC_obj);
         rt_store_attr(m, qstr_from_str("millis"), rt_make_function_n(0, pyb_millis));
 
+        pin_map_init(m);
         gpio_init(m);
 
         rt_store_name(MP_QSTR_pyb, m);
diff --git a/stm/mpconfigport.h b/stm/mpconfigport.h
index 51e4bb9a82..c5614f4bb8 100644
--- a/stm/mpconfigport.h
+++ b/stm/mpconfigport.h
@@ -34,186 +34,7 @@ machine_float_t machine_sqrt(machine_float_t x);
 
 // board specific definitions
 
-// choose 1 of these boards
-//#define PYBOARD3
-#define PYBOARD4
-//#define STM32F4DISC
-//#define NETDUINO_PLUS_2
-
-#if defined (PYBOARD3)
-    #define MICROPY_HW_BOARD_NAME       "PYBv3"
-
-    #define MICROPY_HW_HAS_SWITCH       (1)
-    #define MICROPY_HW_HAS_SDCARD       (1)
-    #define MICROPY_HW_HAS_MMA7660      (1)
-    #define MICROPY_HW_HAS_LIS3DSH      (0)
-    #define MICROPY_HW_HAS_LCD          (0)
-    #define MICROPY_HW_HAS_WLAN         (0)
-    #define MICROPY_HW_ENABLE_RNG       (1)
-    #define MICROPY_HW_ENABLE_RTC       (1)
-    #define MICROPY_HW_ENABLE_TIMER     (1)
-    #define MICROPY_HW_ENABLE_SERVO     (1)
-    #define MICROPY_HW_ENABLE_AUDIO     (0)
-
-    #define USRSW_PORT          (GPIOA)
-    #define USRSW_PIN           (GPIO_Pin_13)
-    #define USRSW_PUPD          (GPIO_PuPd_UP)
-    #define USRSW_EXTI_PIN      (EXTI_PinSource13)
-    #define USRSW_EXTI_PORT     (EXTI_PortSourceGPIOA)
-    #define USRSW_EXTI_LINE     (EXTI_Line13)
-    #define USRSW_EXTI_IRQN     (EXTI15_10_IRQn)
-    #define USRSW_EXTI_EDGE     (EXTI_Trigger_Rising)
-
-    /* LED */
-    #define PYB_LED1_PORT   (GPIOA)
-    #define PYB_LED1_PIN    (GPIO_Pin_8)
-
-    #define PYB_LED2_PORT   (GPIOA)
-    #define PYB_LED2_PIN    (GPIO_Pin_10)
-
-    #define PYB_LED3_PORT   (GPIOC)
-    #define PYB_LED3_PIN    (GPIO_Pin_4)
-
-    #define PYB_LED4_PORT   (GPIOC)
-    #define PYB_LED4_PIN    (GPIO_Pin_5)
-
-    #define PYB_OTYPE       (GPIO_OType_OD)
-
-    #define PYB_LED_ON(port, pin)  (port->BSRRH = pin)
-    #define PYB_LED_OFF(port, pin) (port->BSRRL = pin)
-
-#elif defined (PYBOARD4)
-    #define MICROPY_HW_BOARD_NAME       "PYBv4"
-
-    #define MICROPY_HW_HAS_SWITCH       (1)
-    #define MICROPY_HW_HAS_SDCARD       (1)
-    #define MICROPY_HW_HAS_MMA7660      (1)
-    #define MICROPY_HW_HAS_LIS3DSH      (0)
-    #define MICROPY_HW_HAS_LCD          (1)
-    #define MICROPY_HW_HAS_WLAN         (0)
-    #define MICROPY_HW_ENABLE_RNG       (1)
-    #define MICROPY_HW_ENABLE_RTC       (1)
-    #define MICROPY_HW_ENABLE_TIMER     (1)
-    #define MICROPY_HW_ENABLE_SERVO     (1)
-    #define MICROPY_HW_ENABLE_AUDIO     (0)
-
-    #define USRSW_PORT          (GPIOB)
-    #define USRSW_PIN           (GPIO_Pin_3)
-    #define USRSW_PUPD          (GPIO_PuPd_UP)
-    #define USRSW_EXTI_PIN      (EXTI_PinSource3)
-    #define USRSW_EXTI_PORT     (EXTI_PortSourceGPIOB)
-    #define USRSW_EXTI_LINE     (EXTI_Line3)
-    #define USRSW_EXTI_IRQN     (EXTI3_IRQn)
-    #define USRSW_EXTI_EDGE     (EXTI_Trigger_Rising)
-
-    /* LED */
-    #define PYB_LED1_PORT   (GPIOA)
-    #define PYB_LED1_PIN    (GPIO_Pin_13)
-
-    #define PYB_LED2_PORT   (GPIOA)
-    #define PYB_LED2_PIN    (GPIO_Pin_14)
-
-    #define PYB_LED3_PORT   (GPIOA)
-    #define PYB_LED3_PIN    (GPIO_Pin_15)
-
-    #define PYB_LED4_PORT   (GPIOB)
-    #define PYB_LED4_PIN    (GPIO_Pin_4)
-
-    #define PYB_OTYPE       (GPIO_OType_PP)
-
-    #define PYB_LED_ON(port, pin)  (port->BSRRL = pin)
-    #define PYB_LED_OFF(port, pin) (port->BSRRH = pin)
-
-#elif defined (STM32F4DISC)
-    #define MICROPY_HW_BOARD_NAME       "F4DISC"
-
-    #define MICROPY_HW_HAS_SWITCH       (1)
-    #define MICROPY_HW_HAS_SDCARD       (0)
-    #define MICROPY_HW_HAS_MMA7660      (0)
-    #define MICROPY_HW_HAS_LIS3DSH      (1)
-    #define MICROPY_HW_HAS_LCD          (0)
-    #define MICROPY_HW_HAS_WLAN         (0)
-    #define MICROPY_HW_ENABLE_RNG       (1)
-    #define MICROPY_HW_ENABLE_RTC       (1)
-    #define MICROPY_HW_ENABLE_TIMER     (1)
-    #define MICROPY_HW_ENABLE_SERVO     (0)
-    #define MICROPY_HW_ENABLE_AUDIO     (0)
-
-    #define USRSW_PORT          (GPIOA)
-    #define USRSW_PIN           (GPIO_Pin_0)
-    #define USRSW_PUPD          (GPIO_PuPd_NOPULL)
-    #define USRSW_EXTI_PIN      (EXTI_PinSource0)
-    #define USRSW_EXTI_PORT     (EXTI_PortSourceGPIOA)
-    #define USRSW_EXTI_LINE     (EXTI_Line0)
-    #define USRSW_EXTI_IRQN     (EXTI0_IRQn)
-    #define USRSW_EXTI_EDGE     (EXTI_Trigger_Falling)
-
-    /* LED */
-    #define PYB_LED1_PORT   (GPIOD)
-    #define PYB_LED1_PIN    (GPIO_Pin_14)
-
-    #define PYB_LED2_PORT   (GPIOD)
-    #define PYB_LED2_PIN    (GPIO_Pin_12)
-
-    #define PYB_LED3_PORT   (GPIOD)
-    #define PYB_LED3_PIN    (GPIO_Pin_15)
-
-    #define PYB_LED4_PORT   (GPIOD)
-    #define PYB_LED4_PIN    (GPIO_Pin_13)
-
-    #define PYB_OTYPE       (GPIO_OType_PP)
-
-    #define PYB_LED_ON(port, pin)  (port->BSRRL = pin)
-    #define PYB_LED_OFF(port, pin) (port->BSRRH = pin)
-
-#elif defined (NETDUINO_PLUS_2)
-    #define MICROPY_HW_BOARD_NAME       "NetduinoPlus2"
-
-    #define MICROPY_HW_HAS_SWITCH       (1)
-
-    // On the netuino, the sdcard appears to be wired up as a 1-bit
-    // SPI, so the driver needs to be converted to support that before
-    // we can turn this on.
-    #define MICROPY_HW_HAS_SDCARD       (0)
-    #define MICROPY_HW_HAS_MMA7660      (0)
-    #define MICROPY_HW_HAS_LIS3DSH      (0)
-    #define MICROPY_HW_HAS_LCD          (0)
-    #define MICROPY_HW_HAS_WLAN         (0)
-    #define MICROPY_HW_ENABLE_RNG       (1)
-    #define MICROPY_HW_ENABLE_RTC       (0)
-    #define MICROPY_HW_ENABLE_TIMER     (1)
-    #define MICROPY_HW_ENABLE_SERVO     (1)
-    #define MICROPY_HW_ENABLE_AUDIO     (0)
-
-    #define USRSW_PORT          (GPIOB)
-    #define USRSW_PIN           (GPIO_Pin_11)
-    #define USRSW_PUPD          (GPIO_PuPd_NOPULL)
-    #define USRSW_EXTI_PIN      (EXTI_PinSource11)
-    #define USRSW_EXTI_PORT     (EXTI_PortSourceGPIOB)
-    #define USRSW_EXTI_LINE     (EXTI_Line11)
-    #define USRSW_EXTI_IRQN     (EXTI15_10_IRQn)
-    #define USRSW_EXTI_EDGE     (EXTI_Trigger_Rising)
-
-    /* LED */
-    #define PYB_LED1_PORT   (GPIOA)         // Blue LED
-    #define PYB_LED1_PIN    (GPIO_Pin_10)
-
-    #define PYB_LED2_PORT   (GPIOC)         // White LED (aka Power)
-    #define PYB_LED2_PIN    (GPIO_Pin_13)
-
-    #define PYB_LED3_PORT   (GPIOA)         // Same as Led(1)
-    #define PYB_LED3_PIN    (GPIO_Pin_10)
-
-    #define PYB_LED4_PORT   (GPIOC)         // Same as Led(2)
-    #define PYB_LED4_PIN    (GPIO_Pin_13)
-
-    #define PYB_OTYPE       (GPIO_OType_PP)
-
-    #define PYB_LED_ON(port, pin)  (port->BSRRL = pin)
-    #define PYB_LED_OFF(port, pin) (port->BSRRH = pin)
-
-    #define HSE_VALUE (25000000)
-#endif
+#include "mpconfigboard.h"
 
 #define STM32F40_41xxx
 #define USE_STDPERIPH_DRIVER
diff --git a/stm/pin.c b/stm/pin.c
new file mode 100644
index 0000000000..e7f6998874
--- /dev/null
+++ b/stm/pin.c
@@ -0,0 +1,62 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <stm32f4xx.h>
+
+#include "misc.h"
+#include "mpconfig.h"
+#include "qstr.h"
+#include "obj.h"
+
+#include "pin.h"
+
+void pin_obj_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+    pin_obj_t *self = self_in;
+    print(env, "<Pin %s>", self->name);
+}
+
+mp_obj_t pin_obj_name(mp_obj_t self_in) {
+    pin_obj_t *self = self_in;
+    return MP_OBJ_NEW_QSTR(qstr_from_str(self->name));
+}
+
+mp_obj_t pin_obj_port(mp_obj_t self_in) {
+    pin_obj_t *self = self_in;
+    return MP_OBJ_NEW_SMALL_INT((mp_small_int_t)self->port);
+}
+
+mp_obj_t pin_obj_pin(mp_obj_t self_in) {
+    pin_obj_t *self = self_in;
+    return MP_OBJ_NEW_SMALL_INT((mp_small_int_t)self->pin);
+}
+
+static MP_DEFINE_CONST_FUN_OBJ_1(pin_obj_name_obj, pin_obj_name);
+static MP_DEFINE_CONST_FUN_OBJ_1(pin_obj_port_obj, pin_obj_port);
+static MP_DEFINE_CONST_FUN_OBJ_1(pin_obj_pin_obj, pin_obj_pin);
+
+static const mp_method_t pin_methods[] = {
+    { "name", &pin_obj_name_obj },
+    { "port", &pin_obj_port_obj },
+    { "pin", &pin_obj_pin_obj },
+    { NULL, NULL },
+};
+
+const mp_obj_type_t pin_obj_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_Pin,
+    .print = pin_obj_print,
+    .methods = pin_methods,
+};
+
+void pin_af_obj_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+    pin_af_obj_t *self = self_in;
+    print(env, "<Pin AF %d fn:%d unit:%d typ:%d>", self->idx, self->fn,
+          self->unit, self->type);
+}
+
+const mp_obj_type_t pin_af_obj_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_PinAF,
+    .print = pin_af_obj_print,
+};
+
diff --git a/stm/pin.h b/stm/pin.h
new file mode 100644
index 0000000000..5cfd9fb0f2
--- /dev/null
+++ b/stm/pin.h
@@ -0,0 +1,117 @@
+enum {
+  PORT_A,
+  PORT_B,
+  PORT_C,
+  PORT_D,
+  PORT_E,
+  PORT_F,
+  PORT_G,
+  PORT_H,
+  PORT_I,
+  PORT_J,
+};
+
+enum {
+  AF_FN_TIM,
+  AF_FN_I2C,
+  AF_FN_USART,
+  AF_FN_UART = AF_FN_USART,
+  AF_FN_SPI
+};
+
+enum {
+  AF_PIN_TYPE_TIM_CH1 = 0,
+  AF_PIN_TYPE_TIM_CH2,
+  AF_PIN_TYPE_TIM_CH3,
+  AF_PIN_TYPE_TIM_CH4,
+  AF_PIN_TYPE_TIM_CH1N,
+  AF_PIN_TYPE_TIM_CH2N,
+  AF_PIN_TYPE_TIM_CH3N,
+  AF_PIN_TYPE_TIM_CH1_ETR,
+  AF_PIN_TYPE_TIM_ETR,
+  AF_PIN_TYPE_TIM_BKIN,
+
+  AF_PIN_TYPE_I2C_SDA = 0,
+  AF_PIN_TYPE_I2C_SCL,
+
+  AF_PIN_TYPE_USART_TX = 0,
+  AF_PIN_TYPE_USART_RX,
+  AF_PIN_TYPE_USART_CTS,
+  AF_PIN_TYPE_USART_RTS,
+  AF_PIN_TYPE_USART_CK,
+  AF_PIN_TYPE_UART_TX  = AF_PIN_TYPE_USART_TX,
+  AF_PIN_TYPE_UART_RX  = AF_PIN_TYPE_USART_RX,
+  AF_PIN_TYPE_UART_CTS = AF_PIN_TYPE_USART_CTS,
+  AF_PIN_TYPE_UART_RTS = AF_PIN_TYPE_USART_RTS,
+
+  AF_PIN_TYPE_SPI_MOSI = 0,
+  AF_PIN_TYPE_SPI_MISO,
+  AF_PIN_TYPE_SPI_SCK,
+  AF_PIN_TYPE_SPI_NSS,
+};
+
+typedef struct {
+  mp_obj_base_t base;
+  uint8_t idx;
+  uint8_t fn;
+  uint8_t unit;
+  uint8_t type;
+
+  union {
+    void          *reg;
+    TIM_TypeDef   *TIM;
+    I2C_TypeDef   *I2C;
+    USART_TypeDef *USART;
+    USART_TypeDef *UART;
+    SPI_TypeDef   *SPI;
+  };
+} pin_af_obj_t;
+
+typedef struct {
+  mp_obj_base_t base;
+  const char *name;
+  uint16_t  port   : 4;
+  uint16_t  pin    : 4;
+  uint16_t  num_af : 4;
+  uint16_t pin_mask;
+  GPIO_TypeDef *gpio;
+  const pin_af_obj_t *af;
+} pin_obj_t;
+
+extern const mp_obj_type_t pin_obj_type;
+extern const mp_obj_type_t pin_af_obj_type;
+
+typedef struct {
+  const char  *name;
+  const pin_obj_t *pin;
+} pin_named_pin_t;
+
+extern const pin_named_pin_t pin_board_pins[];
+extern const pin_named_pin_t pin_cpu_pins[];
+
+typedef struct {
+    mp_obj_base_t base;
+    mp_obj_t mapper;
+    mp_obj_t map_dict;
+    bool debug;
+} pin_map_obj_t;
+
+extern pin_map_obj_t pin_map_obj;
+
+typedef struct {
+    mp_obj_base_t base;
+    const char *name;
+    const pin_named_pin_t *named_pins;
+} pin_named_pins_obj_t;
+
+extern const pin_named_pins_obj_t pin_board_pins_obj;
+extern const pin_named_pins_obj_t pin_cpu_pins_obj;
+
+const pin_obj_t *pin_find_named_pin(const pin_named_pin_t *pins, const char *name);
+const pin_af_obj_t *pin_find_af(const pin_obj_t *pin, uint8_t fn, uint8_t unit, uint8_t pin_type);
+
+void pin_map_init(mp_obj_t mod);
+
+// C function for mapping python pin identifier into an ordinal pin number.
+const pin_obj_t *pin_map_user_obj(mp_obj_t user_obj);
+
diff --git a/stm/pin_map.c b/stm/pin_map.c
new file mode 100644
index 0000000000..bd2cfb9e9d
--- /dev/null
+++ b/stm/pin_map.c
@@ -0,0 +1,228 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <stm32f4xx.h>
+
+#include "misc.h"
+#include "mpconfig.h"
+#include "qstr.h"
+#include "obj.h"
+#include "runtime.h"
+#include "nlr.h"
+#include "map.h"
+
+#include "pin.h"
+
+// Usage Model:
+//
+// All Board Pins are predefined as pyb.Pin.board.Name
+//
+//   x1_pin = pyb.Pin.board.X1
+//
+//   g = pyb.gpio(pyb.Pin.board.X1, 0)
+// 
+// CPU pins which correspond to the board pins are available
+// as pyb.cpu.Name. For the CPU pins, the names are the port letter
+// followed by the pin number. On the PYBOARD4, pyb.Pin.board.X1 and
+// pyb.Pin.cpu.B6 are the same pin. 
+//
+// You can also use strings:
+//
+//   g = pyb.gpio('X1', 0)
+//
+// Users can add their own names:
+//
+//   pyb.Pin("LeftMotorDir", pyb.Pin.cpu.C12)
+//   g = pyb.gpio("LeftMotorDir", 0)
+//
+// and can query mappings
+//
+//   pin = pyb.Pin("LeftMotorDir");
+//
+// Users can also add their own mapping function:
+//
+//   def MyMapper(pin_name):
+//      if pin_name == "LeftMotorDir":
+//          return pyb.Pin.cpu.A0
+//
+//   pyb.Pin.mapper(MyMapper)
+//
+// So, if you were to call: pyb.gpio("LeftMotorDir", 0)
+// then "LeftMotorDir" is passed directly to the mapper function.
+//
+// To summarize, the following order determines how things get mapped into
+// an ordinal pin number:
+//
+// 1 - Directly specify a pin object
+// 2 - User supplied mapping function
+// 3 - User supplied mapping (object must be usable as a dictionary key)
+// 4 - Supply a string which matches a board pin
+// 5 - Supply a string which matches a CPU port/pin
+//
+// You can set pyb.Pin.debug(True) to get some debug information about
+// how a particular object gets mapped to a pin.
+
+static void pin_map_obj_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+    (void)self_in;
+    print(env, "<PinMap>");
+}
+
+static mp_obj_t pin_map_call(mp_obj_t self_in, uint n_args, uint n_kw, const mp_obj_t *args) {
+    pin_map_obj_t *self = self_in;
+    rt_check_nargs(n_args, 1, 2, n_kw, false);
+
+    if (n_args > 1) {
+        if (!self->map_dict) {
+            self->map_dict = mp_obj_new_dict(1);
+        }
+        mp_obj_dict_store(self->map_dict, args[0], args[1]);
+        return mp_const_none;
+    }
+
+    // Run an argument through the mapper and return the result.
+    return (mp_obj_t)pin_map_user_obj(args[0]);
+}
+
+static mp_obj_t pin_map_obj_mapper(uint n_args, mp_obj_t *args) {
+    pin_map_obj_t *self = args[0];
+    if (n_args > 1) {
+        self->mapper = args[1];
+        return mp_const_none;
+    }
+    return self->mapper;
+}
+static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pin_map_obj_mapper_obj, 1, 2, pin_map_obj_mapper);
+
+static mp_obj_t pin_map_obj_debug(uint n_args, mp_obj_t *args) {
+    pin_map_obj_t *self = args[0];
+    if (n_args > 1) {
+        self->debug = rt_is_true(args[1]);
+        return mp_const_none;
+    }
+    return MP_BOOL(self->debug);
+}
+static MP_DEFINE_CONST_FUN_OBJ_VAR_BETWEEN(pin_map_obj_debug_obj, 1, 2, pin_map_obj_debug);
+
+static void pin_map_load_attr(mp_obj_t self_in, qstr attr_qstr, mp_obj_t *dest) {
+    (void)self_in;
+    const char *attr = qstr_str(attr_qstr);
+
+    if (strcmp(attr, "mapper") == 0) {
+        dest[0] = (mp_obj_t)&pin_map_obj_mapper_obj;
+        dest[1] = self_in;
+    }
+    if (strcmp(attr, "debug") == 0) {
+        dest[0] = (mp_obj_t)&pin_map_obj_debug_obj;
+        dest[1] = self_in;
+    }
+    if (strcmp(attr, pin_board_pins_obj.name) == 0) {
+        dest[0] = (mp_obj_t)&pin_board_pins_obj;
+        dest[1] = MP_OBJ_NULL;
+    }
+    if (strcmp(attr, pin_cpu_pins_obj.name) == 0) {
+        dest[0] = (mp_obj_t)&pin_cpu_pins_obj;
+        dest[1] = MP_OBJ_NULL;
+    }
+}
+
+static const mp_obj_type_t pin_map_obj_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_PinMap,
+    .print = pin_map_obj_print,
+    .call = pin_map_call,
+    .load_attr = pin_map_load_attr,
+};
+
+static const pin_map_obj_t pin_map_obj_init = {
+    { &pin_map_obj_type },
+    .mapper = MP_OBJ_NULL,
+    .map_dict = MP_OBJ_NULL,
+    .debug = false,
+};
+
+pin_map_obj_t pin_map_obj;
+
+void pin_map_init(mp_obj_t mod) {
+    pin_map_obj = pin_map_obj_init;
+    rt_store_attr(mod, MP_QSTR_Pin, (mp_obj_t)&pin_map_obj);
+}
+
+// C API used to convert a user-supplied pin name  into an ordinal pin number.
+const pin_obj_t *pin_map_user_obj(mp_obj_t user_obj) {
+    const pin_obj_t *pin_obj;
+
+    // If a pin was provided, then use it
+    if (MP_OBJ_IS_TYPE(user_obj, &pin_obj_type)) {
+        pin_obj = user_obj;
+        if (pin_map_obj.debug) {
+            printf("Pin map passed pin ");
+            mp_obj_print((mp_obj_t)pin_obj, PRINT_STR);
+            printf("\n");
+        }
+        return pin_obj;
+    }
+
+    if (pin_map_obj.mapper) {
+        pin_obj = rt_call_function_1(pin_map_obj.mapper, user_obj);
+        if (pin_obj != mp_const_none) {
+            if (!MP_OBJ_IS_TYPE(pin_obj, &pin_obj_type)) {
+                nlr_jump(mp_obj_new_exception_msg(&mp_type_ValueError, "Pin.mapper didn't return a Pin object"));
+            }
+            if (pin_map_obj.debug) {
+                printf("Pin.mapper maps ");
+                mp_obj_print(user_obj, PRINT_REPR);
+                printf(" to ");
+                mp_obj_print((mp_obj_t)pin_obj, PRINT_STR);
+                printf("\n");
+            }
+            return pin_obj;
+        }
+        // The pin mapping function returned mp_const_none, fall through to
+        // other lookup methods.
+    }
+
+    if (pin_map_obj.map_dict) {
+        mp_map_t *pin_map_map = mp_obj_dict_get_map(pin_map_obj.map_dict);
+        mp_map_elem_t *elem = mp_map_lookup(pin_map_map, user_obj, MP_MAP_LOOKUP);
+        if (elem != NULL && elem->value != NULL) {
+            pin_obj = elem->value;
+            if (pin_map_obj.debug) {
+                printf("Pin.map_dict maps ");
+                mp_obj_print(user_obj, PRINT_REPR);
+                printf(" to ");
+                mp_obj_print((mp_obj_t)pin_obj, PRINT_STR);
+                printf("\n");
+            }
+            return pin_obj;
+        }
+    }
+
+    // See if the pin name matches a board pin
+    const char *pin_name = mp_obj_str_get_str(user_obj);
+    pin_obj = pin_find_named_pin(pin_board_pins, pin_name);
+    if (pin_obj) {
+        if (pin_map_obj.debug) {
+            printf("Pin.board maps ");
+            mp_obj_print(user_obj, PRINT_REPR);
+            printf(" to ");
+            mp_obj_print((mp_obj_t)pin_obj, PRINT_STR);
+            printf("\n");
+        }
+        return pin_obj;
+    }
+
+    // See if the pin name matches a cpu pin
+    pin_obj = pin_find_named_pin(pin_cpu_pins, pin_name);
+    if (pin_obj) {
+        if (pin_map_obj.debug) {
+            printf("Pin.cpu maps ");
+            mp_obj_print(user_obj, PRINT_REPR);
+            printf(" to ");
+            mp_obj_print((mp_obj_t)pin_obj, PRINT_STR);
+            printf("\n");
+        }
+        return pin_obj;
+    }
+
+    nlr_jump(mp_obj_new_exception_msg_varg(&mp_type_ValueError, "pin '%s' not a valid pin identifier", pin_name));
+}
diff --git a/stm/pin_named_pins.c b/stm/pin_named_pins.c
new file mode 100644
index 0000000000..d68722b4a1
--- /dev/null
+++ b/stm/pin_named_pins.c
@@ -0,0 +1,67 @@
+#include <stdio.h>
+#include <stdint.h>
+#include <string.h>
+#include <stm32f4xx.h>
+
+#include "misc.h"
+#include "mpconfig.h"
+#include "qstr.h"
+#include "obj.h"
+#include "runtime.h"
+
+#include "pin.h"
+
+static void pin_named_pins_obj_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+    pin_named_pins_obj_t *self = self_in;
+    print(env, "<Pin.%s>", self->name);
+}
+
+static void pin_named_pins_obj_load_attr(mp_obj_t self_in, qstr attr_qstr, mp_obj_t *dest) {
+    pin_named_pins_obj_t *self = self_in;
+    const char *attr = qstr_str(attr_qstr);
+    const pin_obj_t *pin = pin_find_named_pin(self->named_pins, attr);
+    if (pin) {
+        dest[0] = (mp_obj_t)pin;
+        dest[1] = MP_OBJ_NULL;
+    }
+}
+
+static const mp_obj_type_t pin_named_pins_obj_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_PinNamed,
+    .print = pin_named_pins_obj_print,
+    .load_attr = pin_named_pins_obj_load_attr,
+};
+
+const pin_named_pins_obj_t pin_board_pins_obj = {
+    { &pin_named_pins_obj_type },
+    .name = "board",
+    .named_pins = pin_board_pins,
+};
+
+const pin_named_pins_obj_t pin_cpu_pins_obj = {
+    { &pin_named_pins_obj_type },
+    .name = "cpu",
+    .named_pins = pin_cpu_pins,
+};
+
+const pin_obj_t *pin_find_named_pin(const pin_named_pin_t *named_pins, const char *name) {
+    const pin_named_pin_t *named_pin = named_pins;
+    while (named_pin->name) {
+        if (!strcmp(name, named_pin->name)) {
+            return named_pin->pin;
+        }
+        named_pin++;
+    }
+    return NULL;
+}
+
+const pin_af_obj_t *pin_find_af(const pin_obj_t *pin, uint8_t fn, uint8_t unit, uint8_t type) {
+    const pin_af_obj_t *af = pin->af;
+    for (int i = 0; i < pin->num_af; i++, af++) {
+        if (af->fn == fn && af->unit == unit && af->type == type) {
+            return af;
+        }
+    }
+    return NULL;
+}
diff --git a/stm/qstrdefsport.h b/stm/qstrdefsport.h
index 65c4f81a94..3b20e3acd3 100644
--- a/stm/qstrdefsport.h
+++ b/stm/qstrdefsport.h
@@ -36,3 +36,7 @@ Q(File)
 Q(0:/)
 Q(0:/src)
 Q(0:/lib)
+Q(Pin)
+Q(PinMap)
+Q(PinAF)
+Q(PinNamed)