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micropython/ports/samd/machine_uart.c

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/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2020-2021 Damien P. George
* Copyright (c) 2022 Robert Hammelrath
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
* THE SOFTWARE.
*/
#include "py/runtime.h"
#include "py/mphal.h"
#include "py/stream.h"
#include "py/ringbuf.h"
#include "modmachine.h"
#include "samd_soc.h"
#include "pin_af.h"
#include "clock_config.h"
#define DEFAULT_UART_BAUDRATE (115200)
#define DEFAULT_BUFFER_SIZE (256)
#define MIN_BUFFER_SIZE (32)
#define MAX_BUFFER_SIZE (32766)
typedef struct _machine_uart_obj_t {
mp_obj_base_t base;
uint8_t id;
uint32_t baudrate;
uint8_t bits;
uint8_t parity;
uint8_t stop;
uint8_t tx;
sercom_pad_config_t tx_pad_config;
uint8_t rx;
sercom_pad_config_t rx_pad_config;
uint16_t timeout; // timeout waiting for first char (in ms)
uint16_t timeout_char; // timeout waiting between chars (in ms)
bool new;
ringbuf_t read_buffer;
#if MICROPY_HW_UART_TXBUF
ringbuf_t write_buffer;
#endif
} machine_uart_obj_t;
Sercom *sercom_instance[] = SERCOM_INSTS;
STATIC const char *_parity_name[] = {"None", "", "0", "1"}; // Is defined as 0, 2, 3
// Irq handler
// take all bytes from the fifo and store them in the buffer
STATIC void uart_drain_rx_fifo(machine_uart_obj_t *self, Sercom *uart) {
while (uart->USART.INTFLAG.bit.RXC != 0) {
if (ringbuf_free(&self->read_buffer) > 0) {
// 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;
}
}
}
void common_uart_irq_handler(int uart_id) {
machine_uart_obj_t *self = MP_STATE_PORT(sercom_table[uart_id]);
// Handle IRQ
if (self != NULL) {
Sercom *uart = sercom_instance[self->id];
if (uart->USART.INTFLAG.bit.RXC != 0) {
// Now handler the incoming data
uart_drain_rx_fifo(self, uart);
} else if (uart->USART.INTFLAG.bit.DRE != 0) {
#if MICROPY_HW_UART_TXBUF
// handle the outgoing data
if (ringbuf_avail(&self->write_buffer) > 0) {
uart->USART.DATA.bit.DATA = ringbuf_get(&self->write_buffer);
} else {
// Stop the interrupt if there is no more data
uart->USART.INTENCLR.reg = SERCOM_USART_INTENCLR_DRE;
}
#endif
} else {
// Disable the other interrupts, if set by error
uart->USART.INTENCLR.reg = (uint8_t) ~(SERCOM_USART_INTENCLR_DRE | SERCOM_USART_INTENCLR_RXC);
}
}
}
void sercom_enable(Sercom *uart, int state) {
uart->USART.CTRLA.bit.ENABLE = state; // Set the state on/off
// Wait for the Registers to update.
while (uart->USART.SYNCBUSY.bit.ENABLE) {
}
}
STATIC void machine_uart_print(const mp_print_t *print, mp_obj_t self_in, mp_print_kind_t kind) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
mp_printf(print, "UART(%u, baudrate=%u, bits=%u, parity=%s, stop=%u, "
"timeout=%u, timeout_char=%u, rxbuf=%d"
#if MICROPY_HW_UART_TXBUF
", txbuf=%d"
#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
);
}
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};
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} },
{ MP_QSTR_parity, MP_ARG_OBJ, {.u_rom_obj = MP_ROM_INT(-1)} },
{ MP_QSTR_stop, MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_tx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
{ MP_QSTR_rx, MP_ARG_KW_ONLY | MP_ARG_OBJ, {.u_rom_obj = MP_ROM_NONE} },
{ MP_QSTR_timeout, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_timeout_char, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
{ MP_QSTR_rxbuf, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
#if MICROPY_HW_UART_TXBUF
{ MP_QSTR_txbuf, MP_ARG_KW_ONLY | MP_ARG_INT, {.u_int = -1} },
#endif
};
// Parse args
mp_arg_val_t args[MP_ARRAY_SIZE(allowed_args)];
mp_arg_parse_all(n_args, pos_args, kw_args, MP_ARRAY_SIZE(allowed_args), allowed_args, args);
// Set baudrate if configured.
if (args[ARG_baudrate].u_int > 0) {
self->baudrate = args[ARG_baudrate].u_int;
}
// Set bits if configured.
if (args[ARG_bits].u_int > 0) {
self->bits = args[ARG_bits].u_int;
}
// Set parity if configured.
if (args[ARG_parity].u_obj != MP_OBJ_NEW_SMALL_INT(-1)) {
if (args[ARG_parity].u_obj == mp_const_none) {
self->parity = 0;
} else if (mp_obj_get_int(args[ARG_parity].u_obj) & 1) {
self->parity = 1; // odd
} else {
self->parity = 2; // even
}
}
// Set stop bits if configured.
if (args[ARG_stop].u_int > 0) {
self->stop = (args[ARG_stop].u_int - 1) & 1;
}
// Set TX/RX pins if configured.
if (args[ARG_tx].u_obj != mp_const_none) {
self->tx = mp_hal_get_pin_obj(args[ARG_tx].u_obj);
}
if (args[ARG_rx].u_obj != mp_const_none) {
self->rx = mp_hal_get_pin_obj(args[ARG_rx].u_obj);
}
// Set timeout if configured.
if (args[ARG_timeout].u_int >= 0) {
self->timeout = args[ARG_timeout].u_int;
}
// Set timeout_char if configured.
if (args[ARG_timeout_char].u_int >= 0) {
self->timeout_char = args[ARG_timeout_char].u_int;
}
// Set the RX buffer size if configured.
size_t rxbuf_len = DEFAULT_BUFFER_SIZE;
if (args[ARG_rxbuf].u_int > 0) {
rxbuf_len = args[ARG_rxbuf].u_int;
if (rxbuf_len < MIN_BUFFER_SIZE) {
rxbuf_len = MIN_BUFFER_SIZE;
} else if (rxbuf_len > MAX_BUFFER_SIZE) {
mp_raise_ValueError(MP_ERROR_TEXT("rxbuf too large"));
}
}
#if MICROPY_HW_UART_TXBUF
// Set the TX buffer size if configured.
size_t txbuf_len = DEFAULT_BUFFER_SIZE;
if (args[ARG_txbuf].u_int > 0) {
txbuf_len = args[ARG_txbuf].u_int;
if (txbuf_len < MIN_BUFFER_SIZE) {
txbuf_len = MIN_BUFFER_SIZE;
} else if (txbuf_len > MAX_BUFFER_SIZE) {
mp_raise_ValueError(MP_ERROR_TEXT("txbuf too large"));
}
}
#endif
// Initialise the UART peripheral if any arguments given, or it was not initialised previously.
if (n_args > 0 || kw_args->used > 0 || self->new) {
self->new = false;
// Check the rx/tx pin assignments
if (self->tx == 0xff || self->rx == 0xff || (self->tx / 4) != (self->rx / 4)) {
mp_raise_ValueError(MP_ERROR_TEXT("Non-matching or missing rx/tx"));
}
self->rx_pad_config = get_sercom_config(self->rx, self->id);
self->tx_pad_config = get_sercom_config(self->tx, self->id);
// Make sure timeout_char is at least as long as a whole character (13 bits to be safe).
uint32_t min_timeout_char = 13000 / self->baudrate + 1;
if (self->timeout_char < min_timeout_char) {
self->timeout_char = min_timeout_char;
}
// Allocate the RX/TX buffers.
ringbuf_alloc(&(self->read_buffer), rxbuf_len + 1);
#if MICROPY_HW_UART_TXBUF
ringbuf_alloc(&(self->write_buffer), txbuf_len + 1);
#endif
// Step 1: Configure the Pin mux.
mp_hal_set_pin_mux(self->rx, self->rx_pad_config.alt_fct);
mp_hal_set_pin_mux(self->tx, self->tx_pad_config.alt_fct);
// Next: Set up the clocks
enable_sercom_clock(self->id);
// Next: Configure the USART
Sercom *uart = sercom_instance[self->id];
// Reset (clear) the peripheral registers.
while (uart->USART.SYNCBUSY.bit.SWRST) {
}
uart->USART.CTRLA.bit.SWRST = 1; // Reset all Registers, disable peripheral
while (uart->USART.SYNCBUSY.bit.SWRST) {
}
uint8_t txpo = self->tx_pad_config.pad_nr;
#if defined(MCU_SAMD21)
if (self->tx_pad_config.pad_nr == 2) { // Map pad 2 to TXPO = 1
txpo = 1;
} else
#endif
if (self->tx_pad_config.pad_nr != 0) {
mp_raise_ValueError(MP_ERROR_TEXT("invalid tx pin"));
}
uart->USART.CTRLA.reg =
SERCOM_USART_CTRLA_DORD // Data order
| SERCOM_USART_CTRLA_FORM(self->parity != 0 ? 1 : 0) // Enable parity or not
| SERCOM_USART_CTRLA_RXPO(self->rx_pad_config.pad_nr) // Set Pad#
| SERCOM_USART_CTRLA_TXPO(txpo) // Set Pad#
| SERCOM_USART_CTRLA_MODE(1) // USART with internal clock
;
uart->USART.CTRLB.reg =
SERCOM_USART_CTRLB_RXEN // Enable Rx & Tx
| SERCOM_USART_CTRLB_TXEN
| ((self->parity & 1) << SERCOM_USART_CTRLB_PMODE_Pos)
| (self->stop << SERCOM_USART_CTRLB_SBMODE_Pos)
| SERCOM_USART_CTRLB_CHSIZE((self->bits & 7) | (self->bits & 1))
;
while (uart->USART.SYNCBUSY.bit.CTRLB) {
}
// USART is driven by the clock of GCLK Generator 2, freq by get_peripheral_freq()
// baud rate; 65536 * (1 - 16 * 115200/bus_freq)
uint32_t baud = 65536 - ((uint64_t)(65536 * 16) * self->baudrate + get_peripheral_freq() / 2) / get_peripheral_freq();
uart->USART.BAUD.bit.BAUD = baud; // Set Baud
sercom_register_irq(self->id, &common_uart_irq_handler);
// Enable RXC interrupt
uart->USART.INTENSET.reg = SERCOM_USART_INTENSET_RXC;
#if defined(MCU_SAMD21)
NVIC_EnableIRQ(SERCOM0_IRQn + self->id);
#elif defined(MCU_SAMD51)
NVIC_EnableIRQ(SERCOM0_0_IRQn + 4 * self->id + 2);
#endif
#if MICROPY_HW_UART_TXBUF
// Enable DRE interrupt
// SAMD21 has just 1 IRQ for all USART events, so no need for an additional NVIC enable
#if defined(MCU_SAMD51)
NVIC_EnableIRQ(SERCOM0_0_IRQn + 4 * self->id + 0);
#endif
#endif
sercom_enable(uart, 1);
}
return MP_OBJ_FROM_PTR(self);
}
STATIC mp_obj_t machine_uart_make_new(const mp_obj_type_t *type, size_t n_args, size_t n_kw, const mp_obj_t *args) {
mp_arg_check_num(n_args, n_kw, 1, MP_OBJ_FUN_ARGS_MAX, true);
// Get UART bus.
int uart_id = mp_obj_get_int(args[0]);
if (uart_id < 0 || uart_id > SERCOM_INST_NUM) {
mp_raise_msg_varg(&mp_type_ValueError, MP_ERROR_TEXT("UART(%d) doesn't exist"), uart_id);
}
// Create the UART object and fill it with defaults.
machine_uart_obj_t *self = mp_obj_malloc(machine_uart_obj_t, &machine_uart_type);
self->id = uart_id;
self->baudrate = DEFAULT_UART_BAUDRATE;
self->bits = 8;
self->stop = 0;
self->timeout = 1;
self->timeout_char = 1;
self->tx = 0xff;
self->rx = 0xff;
self->new = true;
MP_STATE_PORT(sercom_table[uart_id]) = self;
mp_map_t kw_args;
mp_map_init_fixed_table(&kw_args, n_kw, args + n_args);
return machine_uart_init_helper(self, n_args - 1, args + 1, &kw_args);
}
// uart.init(baud, [kwargs])
STATIC mp_obj_t machine_uart_init(size_t n_args, const mp_obj_t *args, mp_map_t *kw_args) {
return machine_uart_init_helper(args[0], n_args - 1, args + 1, kw_args);
}
MP_DEFINE_CONST_FUN_OBJ_KW(machine_uart_init_obj, 1, machine_uart_init);
STATIC mp_obj_t machine_uart_deinit(mp_obj_t self_in) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
// Check if it is the active object.
if (MP_STATE_PORT(sercom_table)[self->id] == self) {
Sercom *uart = sercom_instance[self->id];
// Disable interrupts and de-register the IRQ
if (uart) {
uart->USART.INTENCLR.reg = 0xff;
sercom_register_irq(self->id, NULL);
sercom_enable(uart, 0);
}
}
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_deinit_obj, machine_uart_deinit);
STATIC mp_obj_t machine_uart_any(mp_obj_t self_in) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
return MP_OBJ_NEW_SMALL_INT(ringbuf_avail(&self->read_buffer));
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_any_obj, machine_uart_any);
STATIC mp_obj_t machine_uart_sendbreak(mp_obj_t self_in) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
uint32_t break_time_us = 13 * 1000000 / self->baudrate;
// Wait for the tx buffer to drain.
#if MICROPY_HW_UART_TXBUF
while (ringbuf_avail(&self->write_buffer) > 0) {
MICROPY_EVENT_POLL_HOOK
}
#endif
// Wait for the TX queue & register to clear
// Since the flags are not safe, just wait sufficiently long.
mp_hal_delay_us(2 * break_time_us);
// Disable MUX
PORT->Group[self->tx / 32].PINCFG[self->tx % 32].bit.PMUXEN = 0;
// Set TX pin to low for break time
mp_hal_pin_low(self->tx);
mp_hal_delay_us(break_time_us);
mp_hal_pin_high(self->tx);
// Enable Mux again
mp_hal_set_pin_mux(self->tx, self->tx_pad_config.alt_fct);
return mp_const_none;
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_sendbreak_obj, machine_uart_sendbreak);
STATIC mp_obj_t machine_uart_txdone(mp_obj_t self_in) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
Sercom *uart = sercom_instance[self->id];
if (uart->USART.INTFLAG.bit.DRE
#if MICROPY_HW_UART_TXBUF
&& ringbuf_avail(&self->write_buffer) == 0
#endif
&& uart->USART.INTFLAG.bit.TXC) {
return mp_const_true;
} else {
return mp_const_false;
}
}
STATIC MP_DEFINE_CONST_FUN_OBJ_1(machine_uart_txdone_obj, machine_uart_txdone);
STATIC const mp_rom_map_elem_t machine_uart_locals_dict_table[] = {
{ MP_ROM_QSTR(MP_QSTR_init), MP_ROM_PTR(&machine_uart_init_obj) },
{ MP_ROM_QSTR(MP_QSTR_deinit), MP_ROM_PTR(&machine_uart_deinit_obj) },
{ MP_ROM_QSTR(MP_QSTR_any), MP_ROM_PTR(&machine_uart_any_obj) },
{ MP_ROM_QSTR(MP_QSTR_sendbreak), MP_ROM_PTR(&machine_uart_sendbreak_obj) },
{ MP_ROM_QSTR(MP_QSTR_txdone), MP_ROM_PTR(&machine_uart_txdone_obj) },
{ MP_ROM_QSTR(MP_QSTR_flush), MP_ROM_PTR(&mp_stream_flush_obj) },
{ MP_ROM_QSTR(MP_QSTR_read), MP_ROM_PTR(&mp_stream_read_obj) },
{ MP_ROM_QSTR(MP_QSTR_readline), MP_ROM_PTR(&mp_stream_unbuffered_readline_obj) },
{ MP_ROM_QSTR(MP_QSTR_readinto), MP_ROM_PTR(&mp_stream_readinto_obj) },
{ MP_ROM_QSTR(MP_QSTR_write), MP_ROM_PTR(&mp_stream_write_obj) },
};
STATIC MP_DEFINE_CONST_DICT(machine_uart_locals_dict, machine_uart_locals_dict_table);
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);
uint64_t t = mp_hal_ticks_ms_64() + self->timeout;
uint64_t timeout_char = self->timeout_char;
uint8_t *dest = buf_in;
for (size_t i = 0; i < size; i++) {
// Wait for the first/next character
while (ringbuf_avail(&self->read_buffer) == 0) {
if (mp_hal_ticks_ms_64() > t) { // timed out
if (i <= 0) {
*errcode = MP_EAGAIN;
return MP_STREAM_ERROR;
} else {
return i;
}
}
MICROPY_EVENT_POLL_HOOK
}
*dest++ = ringbuf_get(&(self->read_buffer));
t = mp_hal_ticks_ms_64() + timeout_char;
}
return size;
}
STATIC mp_uint_t machine_uart_write(mp_obj_t self_in, const void *buf_in, mp_uint_t size, int *errcode) {
machine_uart_obj_t *self = MP_OBJ_TO_PTR(self_in);
size_t i = 0;
const uint8_t *src = buf_in;
Sercom *uart = sercom_instance[self->id];
#if MICROPY_HW_UART_TXBUF
uint64_t t = mp_hal_ticks_ms_64() + self->timeout;
while (i < size) {
// Wait for the first/next character to be sent.
while (ringbuf_free(&(self->write_buffer)) == 0) {
if (mp_hal_ticks_ms_64() > t) { // timed out
if (i <= 0) {
*errcode = MP_EAGAIN;
return MP_STREAM_ERROR;
} else {
return i;
}
}
MICROPY_EVENT_POLL_HOOK
}
ringbuf_put(&(self->write_buffer), *src++);
i++;
uart->USART.INTENSET.reg = SERCOM_USART_INTENSET_DRE; // kick off the IRQ
}
#else
while (i < size) {
while (!(uart->USART.INTFLAG.bit.DRE)) {
}
uart->USART.DATA.bit.DATA = *src++;
i++;
}
#endif
return size;
}
STATIC mp_uint_t machine_uart_ioctl(mp_obj_t self_in, mp_uint_t request, mp_uint_t arg, int *errcode) {
machine_uart_obj_t *self = self_in;
mp_uint_t ret;
Sercom *uart = sercom_instance[self->id];
if (request == MP_STREAM_POLL) {
uintptr_t flags = arg;
ret = 0;
if ((flags & MP_STREAM_POLL_RD) && (uart->USART.INTFLAG.bit.RXC != 0 || ringbuf_avail(&self->read_buffer) > 0)) {
ret |= MP_STREAM_POLL_RD;
}
if ((flags & MP_STREAM_POLL_WR) && (uart->USART.INTFLAG.bit.DRE != 0
#if MICROPY_HW_UART_TXBUF
|| ringbuf_avail(&self->write_buffer) > 0
#endif
)) {
ret |= MP_STREAM_POLL_WR;
}
} else if (request == MP_STREAM_FLUSH) {
// The timeout is defined by the buffer size and the baudrate.
// Take the worst case assumtions at 13 bit symbol size times 2.
uint64_t timeout = mp_hal_ticks_ms_64() + (3
#if MICROPY_HW_UART_TXBUF
+ self->write_buffer.size
#endif
) * 13000 * 2 / self->baudrate;
do {
if (machine_uart_txdone((mp_obj_t)self) == mp_const_true) {
return 0;
}
MICROPY_EVENT_POLL_HOOK
} while (mp_hal_ticks_ms_64() < timeout);
*errcode = MP_ETIMEDOUT;
ret = MP_STREAM_ERROR;
} else {
*errcode = MP_EINVAL;
ret = MP_STREAM_ERROR;
}
return ret;
}
STATIC const mp_stream_p_t uart_stream_p = {
.read = machine_uart_read,
.write = machine_uart_write,
.ioctl = machine_uart_ioctl,
.is_text = false,
};
MP_DEFINE_CONST_OBJ_TYPE(
machine_uart_type,
MP_QSTR_UART,
MP_TYPE_FLAG_ITER_IS_STREAM,
make_new, machine_uart_make_new,
print, machine_uart_print,
protocol, &uart_stream_p,
locals_dict, &machine_uart_locals_dict
);
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