stmhal: Add servo driver.

5 files changed, 151 insertions, 6 deletions

diff --git a/stmhal/Makefile b/stmhal/Makefile
index 60e5fde3d3..938871aefb 100644
--- a/stmhal/Makefile
+++ b/stmhal/Makefile
@@ -89,8 +89,8 @@ SRC_C = \
 	diskio.c \
 	lcd.c \
 	accel.c \
+	servo.c \
 
-#	servo.c \
 #	timer.c \
 #	audio.c \
 #	i2c.c \
diff --git a/stmhal/main.c b/stmhal/main.c
index 2b4daa3705..6511891a1b 100644
--- a/stmhal/main.c
+++ b/stmhal/main.c
@@ -36,8 +36,8 @@
 #include "ff.h"
 #include "lcd.h"
 #include "accel.h"
-#if 0
 #include "servo.h"
+#if 0
 #include "timer.h"
 #include "pybwlan.h"
 #include "pin.h"
@@ -254,12 +254,12 @@ soft_reset:
     rng_init();
 #endif
 
-#if 0
 #if MICROPY_HW_ENABLE_SERVO
     // servo
     servo_init();
 #endif
 
+#if 0
 #if MICROPY_HW_ENABLE_TIMER
     // timer
     timer_init();
diff --git a/stmhal/pybmodule.c b/stmhal/pybmodule.c
index afb3b2e60e..09cdf83b8a 100644
--- a/stmhal/pybmodule.c
+++ b/stmhal/pybmodule.c
@@ -23,8 +23,8 @@
 #include "storage.h"
 #include "sdcard.h"
 #include "accel.h"
-#if 0
 #include "servo.h"
+#if 0
 #include "usb.h"
 #include "i2c.h"
 #include "adc.h"
@@ -231,13 +231,11 @@ STATIC const mp_map_elem_t pyb_module_globals_table[] = {
     { MP_OBJ_NEW_QSTR(MP_QSTR_rtc_info), (mp_obj_t)&pyb_rtc_info_obj },
 #endif
 
-#if 0
 #if MICROPY_HW_ENABLE_SERVO
     { MP_OBJ_NEW_QSTR(MP_QSTR_pwm), (mp_obj_t)&pyb_pwm_set_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_servo), (mp_obj_t)&pyb_servo_set_obj },
     { MP_OBJ_NEW_QSTR(MP_QSTR_Servo), (mp_obj_t)&pyb_Servo_obj },
 #endif
-#endif
 
 #if MICROPY_HW_HAS_SWITCH
     { MP_OBJ_NEW_QSTR(MP_QSTR_switch), (mp_obj_t)&pyb_switch_obj },
diff --git a/stmhal/servo.c b/stmhal/servo.c
new file mode 100644
index 0000000000..1be18b8a4e
--- /dev/null
+++ b/stmhal/servo.c
@@ -0,0 +1,142 @@
+#include <stdio.h>
+
+#include "stm32f4xx_hal.h"
+
+#include "misc.h"
+#include "mpconfig.h"
+#include "qstr.h"
+#include "obj.h"
+#include "servo.h"
+
+// this servo driver uses hardware PWM to drive servos on PA0, PA1, PA2, PA3 = X1, X2, X3, X4
+// TIM2 and TIM5 have CH1, CH2, CH3, CH4 on PA0-PA3 respectively
+// they are both 32-bit counters with 16-bit prescaler
+// we use TIM2
+
+STATIC TIM_HandleTypeDef servo_TimHandle;
+
+void servo_init(void) {
+    // TIM2 clock enable
+    __TIM2_CLK_ENABLE();
+
+    // PWM clock configuration
+    servo_TimHandle.Instance = TIM2;
+    servo_TimHandle.Init.Period = 2000; // timer cycles at 50Hz
+    servo_TimHandle.Init.Prescaler = ((SystemCoreClock / 2) / 100000) - 1; // timer runs at 100kHz
+    servo_TimHandle.Init.ClockDivision = 0;
+    servo_TimHandle.Init.CounterMode = TIM_COUNTERMODE_UP;
+    HAL_TIM_PWM_Init(&servo_TimHandle);
+}
+
+STATIC void servo_init_channel(int channel_in) {
+    uint32_t pin;
+    uint32_t channel;
+    switch (channel_in) {
+        case 1: pin = GPIO_PIN_0; channel = TIM_CHANNEL_1; break;
+        case 2: pin = GPIO_PIN_1; channel = TIM_CHANNEL_2; break;
+        case 3: pin = GPIO_PIN_2; channel = TIM_CHANNEL_3; break;
+        case 4: pin = GPIO_PIN_3; channel = TIM_CHANNEL_4; break;
+        default: return;
+    }
+
+    // GPIO configuration
+    GPIO_InitTypeDef GPIO_InitStructure;
+    GPIO_InitStructure.Pin = pin;
+    GPIO_InitStructure.Mode = GPIO_MODE_AF_PP;
+    GPIO_InitStructure.Speed = GPIO_SPEED_FAST;
+    GPIO_InitStructure.Pull = GPIO_NOPULL;
+    GPIO_InitStructure.Alternate = GPIO_AF1_TIM2;
+    HAL_GPIO_Init(GPIOA, &GPIO_InitStructure);
+
+    // PWM mode configuration
+    TIM_OC_InitTypeDef oc_init;
+    oc_init.OCMode = TIM_OCMODE_PWM1;
+    oc_init.Pulse = 150; // units of 10us
+    oc_init.OCPolarity = TIM_OCPOLARITY_HIGH;
+    oc_init.OCFastMode = TIM_OCFAST_DISABLE;
+    HAL_TIM_PWM_ConfigChannel(&servo_TimHandle, &oc_init, channel);
+
+    // start PWM
+    HAL_TIM_PWM_Start(&servo_TimHandle, channel);
+}
+
+/******************************************************************************/
+// Micro Python bindings
+
+STATIC mp_obj_t pyb_servo_set(mp_obj_t port, mp_obj_t value) {
+    int p = mp_obj_get_int(port);
+    int v = mp_obj_get_int(value);
+    if (v < 50) { v = 50; }
+    if (v > 250) { v = 250; }
+    switch (p) {
+        case 1: TIM2->CCR1 = v; break;
+        case 2: TIM2->CCR2 = v; break;
+        case 3: TIM2->CCR3 = v; break;
+        case 4: TIM2->CCR4 = v; break;
+    }
+    return mp_const_none;
+}
+
+MP_DEFINE_CONST_FUN_OBJ_2(pyb_servo_set_obj, pyb_servo_set);
+
+STATIC mp_obj_t pyb_pwm_set(mp_obj_t period, mp_obj_t pulse) {
+    int pe = mp_obj_get_int(period);
+    int pu = mp_obj_get_int(pulse);
+    TIM2->ARR = pe;
+    TIM2->CCR3 = pu;
+    return mp_const_none;
+}
+
+MP_DEFINE_CONST_FUN_OBJ_2(pyb_pwm_set_obj, pyb_pwm_set);
+
+typedef struct _pyb_servo_obj_t {
+    mp_obj_base_t base;
+    uint servo_id;
+} pyb_servo_obj_t;
+
+STATIC void servo_obj_print(void (*print)(void *env, const char *fmt, ...), void *env, mp_obj_t self_in, mp_print_kind_t kind) {
+    pyb_servo_obj_t *self = self_in;
+    print(env, "<Servo %lu>", self->servo_id);
+}
+
+STATIC mp_obj_t servo_obj_angle(mp_obj_t self_in, mp_obj_t angle) {
+    pyb_servo_obj_t *self = self_in;
+#if MICROPY_ENABLE_FLOAT
+    machine_int_t v = 152 + 85.0 * mp_obj_get_float(angle) / 90.0;
+#else
+    machine_int_t v = 152 + 85 * mp_obj_get_int(angle) / 90;
+#endif
+    if (v < 65) { v = 65; }
+    if (v > 210) { v = 210; }
+    switch (self->servo_id) {
+        case 1: TIM2->CCR1 = v; break;
+        case 2: TIM2->CCR2 = v; break;
+        case 3: TIM2->CCR3 = v; break;
+        case 4: TIM2->CCR4 = v; break;
+    }
+    return mp_const_none;
+}
+
+STATIC MP_DEFINE_CONST_FUN_OBJ_2(servo_obj_angle_obj, servo_obj_angle);
+
+STATIC const mp_method_t servo_methods[] = {
+    { "angle", &servo_obj_angle_obj },
+    { NULL, NULL },
+};
+
+STATIC const mp_obj_type_t servo_obj_type = {
+    { &mp_type_type },
+    .name = MP_QSTR_Servo,
+    .print = servo_obj_print,
+    .methods = servo_methods,
+};
+
+STATIC mp_obj_t pyb_Servo(mp_obj_t servo_id) {
+    pyb_servo_obj_t *o = m_new_obj(pyb_servo_obj_t);
+    o->base.type = &servo_obj_type;
+    o->servo_id = mp_obj_get_int(servo_id);
+    servo_init_channel(o->servo_id);
+    return o;
+}
+
+MP_DEFINE_CONST_FUN_OBJ_1(pyb_Servo_obj, pyb_Servo);
diff --git a/stmhal/servo.h b/stmhal/servo.h
new file mode 100644
index 0000000000..bb3edd97a2
--- /dev/null
+++ b/stmhal/servo.h
@@ -0,0 +1,5 @@
+void servo_init(void);
+
+MP_DECLARE_CONST_FUN_OBJ(pyb_servo_set_obj);
+MP_DECLARE_CONST_FUN_OBJ(pyb_pwm_set_obj);
+MP_DECLARE_CONST_FUN_OBJ(pyb_Servo_obj);