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-rw-r--r--docs/samd/pinout.rst8
-rw-r--r--ports/samd/machine_uart.c72
-rw-r--r--ports/samd/mcu/samd51/mpconfigmcu.h3
3 files changed, 73 insertions, 10 deletions
diff --git a/docs/samd/pinout.rst b/docs/samd/pinout.rst
index 702da2c178..64db455eac 100644
--- a/docs/samd/pinout.rst
+++ b/docs/samd/pinout.rst
@@ -83,7 +83,9 @@ Examples for Adafruit ItsyBitsy M0 Express:
- uart 4 at pins D2/D5
- uart 5 at pins SCL/SDA
-or other combinations.
+or other combinations. For hardware flow control, tx must be at pad 0, rx at pad 1,
+rts at pad 2 and cts at pad 3. This applies for instance to
+UART 3 or UART 1 at the pins D13/D11/D10/D12 for rx/tx/rts/cts.
SAMD21 I2C assignments
``````````````````````
@@ -214,7 +216,9 @@ Examples for Adafruit ItsyBitsy 4 Express:
- uart 4 at pins SDA/SCL
- uart 5 at pins D12/D13
-or other combinations.
+or other combinations. For hardware flow control, tx must be at pad 0, rx at pad 1,
+rts at pad 2 and cts at pad 3. This applies for instance to
+UART 5 at the pins D12/D13/D10/D11 for rx/tx/rts/cts.
SAMD51 I2C assignments
``````````````````````
diff --git a/ports/samd/machine_uart.c b/ports/samd/machine_uart.c
index 8028d8872d..b95e158b3c 100644
--- a/ports/samd/machine_uart.c
+++ b/ports/samd/machine_uart.c
@@ -40,6 +40,8 @@
#define DEFAULT_BUFFER_SIZE (256)
#define MIN_BUFFER_SIZE (32)
#define MAX_BUFFER_SIZE (32766)
+#define FLOW_CONTROL_RTS (1)
+#define FLOW_CONTROL_CTS (2)
typedef struct _machine_uart_obj_t {
mp_obj_base_t base;
@@ -49,9 +51,15 @@ typedef struct _machine_uart_obj_t {
uint8_t parity;
uint8_t stop;
uint8_t tx;
- sercom_pad_config_t tx_pad_config;
uint8_t rx;
+ sercom_pad_config_t tx_pad_config;
sercom_pad_config_t rx_pad_config;
+ #if MICROPY_HW_UART_RTSCTS
+ uint8_t rts;
+ uint8_t cts;
+ sercom_pad_config_t rts_pad_config;
+ sercom_pad_config_t cts_pad_config;
+ #endif
uint16_t timeout; // timeout waiting for first char (in ms)
uint16_t timeout_char; // timeout waiting between chars (in ms)
bool new;
@@ -96,11 +104,10 @@ STATIC void uart_drain_rx_fifo(machine_uart_obj_t *self, Sercom *uart) {
// get a byte from uart and put into the buffer
ringbuf_put(&(self->read_buffer), uart->USART.DATA.bit.DATA);
} else {
- // if the buffer is full, discard the data for now
- // t.b.d.: flow control
- uint32_t temp;
- (void)temp;
- temp = uart->USART.DATA.bit.DATA;
+ // if the buffer is full, disable the RX interrupt
+ // allowing RTS to come up. It will be re-enabled by the next read
+ uart->USART.INTENCLR.reg = SERCOM_USART_INTENSET_RXC;
+ break;
}
}
}
@@ -137,18 +144,25 @@ STATIC void machine_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_pri
#if MICROPY_HW_UART_TXBUF
", txbuf=%d"
#endif
+ #if MICROPY_HW_UART_RTSCTS
+ ", rts=%s, cts=%s"
+ #endif
")",
self->id, self->baudrate, self->bits, _parity_name[self->parity],
self->stop + 1, self->timeout, self->timeout_char, self->read_buffer.size - 1
#if MICROPY_HW_UART_TXBUF
, self->write_buffer.size - 1
#endif
+ #if MICROPY_HW_UART_RTSCTS
+ , self->rts != 0xff ? pin_name(self->rts) : "None"
+ , self->cts != 0xff ? pin_name(self->cts) : "None"
+ #endif
);
}
STATIC mp_obj_t machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args, const mp_obj_t *pos_args, mp_map_t *kw_args) {
enum { ARG_baudrate, ARG_bits, ARG_parity, ARG_stop, ARG_tx, ARG_rx,
- ARG_timeout, ARG_timeout_char, ARG_rxbuf, ARG_txbuf};
+ ARG_timeout, ARG_timeout_char, ARG_rxbuf, ARG_txbuf, ARG_rts, ARG_cts };
static const mp_arg_t allowed_args[] = {
{ MP_QSTR_baudrate, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_bits, MP_ARG_INT, {.u_int = -1} },
@@ -162,6 +176,10 @@ STATIC mp_obj_t machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args
#if MICROPY_HW_UART_TXBUF
{ MP_QSTR_txbuf, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
#endif
+ #if MICROPY_HW_UART_RTSCTS
+ { MP_QSTR_rts, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+ { MP_QSTR_cts, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
+ #endif
};
// Parse args
@@ -201,6 +219,25 @@ STATIC mp_obj_t machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args
if (args[ARG_rx].u_obj != mp_const_none) {
self->rx = mp_hal_get_pin_obj(args[ARG_rx].u_obj);
}
+ #if MICROPY_HW_UART_RTSCTS
+ uint8_t flow_control = 0;
+ // Set RTS/CTS pins if configured.
+ if (args[ARG_rts].u_obj != mp_const_none) {
+ self->rts = mp_hal_get_pin_obj(args[ARG_rts].u_obj);
+ self->rts_pad_config = get_sercom_config(self->rts, self->id);
+ flow_control = FLOW_CONTROL_RTS;
+ }
+ if (args[ARG_cts].u_obj != mp_const_none) {
+ self->cts = mp_hal_get_pin_obj(args[ARG_cts].u_obj);
+ self->cts_pad_config = get_sercom_config(self->cts, self->id);
+ flow_control |= FLOW_CONTROL_CTS;
+ }
+ // rts only flow control is not allowed. Otherwise the state of the
+ // cts pin is undefined.
+ if (flow_control == FLOW_CONTROL_RTS) {
+ mp_raise_ValueError(MP_ERROR_TEXT("cts missing for flow control"));
+ }
+ #endif
// Set timeout if configured.
if (args[ARG_timeout].u_int >= 0) {
@@ -282,8 +319,18 @@ STATIC mp_obj_t machine_uart_init_helper(machine_uart_obj_t *self, size_t n_args
} else
#endif
if (self->tx_pad_config.pad_nr != 0) {
- mp_raise_ValueError(MP_ERROR_TEXT("invalid tx pin"));
+ mp_raise_ValueError(MP_ERROR_TEXT("invalid UART pin"));
+ }
+ #if MICROPY_HW_UART_RTSCTS
+ if ((flow_control & FLOW_CONTROL_RTS) && self->rts_pad_config.pad_nr == 2) {
+ txpo = 2;
+ mp_hal_set_pin_mux(self->rts, self->rts_pad_config.alt_fct);
+ }
+ if ((flow_control & FLOW_CONTROL_CTS) && self->cts_pad_config.pad_nr == 3) {
+ txpo = 2;
+ mp_hal_set_pin_mux(self->cts, self->cts_pad_config.alt_fct);
}
+ #endif
uart->USART.CTRLA.reg =
SERCOM_USART_CTRLA_DORD // Data order
@@ -349,6 +396,10 @@ STATIC mp_obj_t machine_uart_make_new(const mp_obj_type_t *type, size_t n_args,
self->timeout_char = 1;
self->tx = 0xff;
self->rx = 0xff;
+ #if MICROPY_HW_UART_RTSCTS
+ self->rts = 0xff;
+ self->cts = 0xff;
+ #endif
self->new = true;
MP_STATE_PORT(sercom_table[uart_id]) = self;
@@ -444,6 +495,7 @@ STATIC MP_DEFINE_CONST_DICT(machine_uart_locals_dict, machine_uart_locals_dict_t
STATIC mp_uint_t machine_uart_read(mp_obj_t self_in, void *buf_in, mp_uint_t size, int *errcode) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
+ Sercom *uart = sercom_instance[self->id];
uint64_t t = mp_hal_ticks_ms_64() + self->timeout;
uint64_t timeout_char = self->timeout_char;
uint8_t *dest = buf_in;
@@ -463,6 +515,10 @@ STATIC mp_uint_t machine_uart_read(mp_obj_t self_in, void *buf_in, mp_uint_t siz
}
*dest++ = ringbuf_get(&(self->read_buffer));
t = mp_hal_ticks_ms_64() + timeout_char;
+ // (Re-)Enable RXC interrupt
+ if ((uart->USART.INTENSET.reg & SERCOM_USART_INTENSET_RXC) == 0) {
+ uart->USART.INTENSET.reg = SERCOM_USART_INTENSET_RXC;
+ }
}
return size;
}
diff --git a/ports/samd/mcu/samd51/mpconfigmcu.h b/ports/samd/mcu/samd51/mpconfigmcu.h
index 0598c353d6..07d4696901 100644
--- a/ports/samd/mcu/samd51/mpconfigmcu.h
+++ b/ports/samd/mcu/samd51/mpconfigmcu.h
@@ -46,6 +46,9 @@ unsigned long trng_random_u32(void);
#ifndef MICROPY_HW_UART_TXBUF
#define MICROPY_HW_UART_TXBUF (1)
#endif
+#ifndef MICROPY_HW_UART_RTSCTS
+#define MICROPY_HW_UART_RTSCTS (1)
+#endif
#define CPU_FREQ (120000000)
#define DFLL48M_FREQ (48000000)
generated by cgit v1.2.3 (git 2.39.1) at 2025-05-16 21:04:42 +0000