circuitpython/ports/atmel-samd/common-hal/busio/UART.c

392 lines
14 KiB
C

/*
* This file is part of the MicroPython project, http://micropython.org/
*
* The MIT License (MIT)
*
* Copyright (c) 2016 Damien P. George
*
* 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 "shared-bindings/microcontroller/__init__.h"
#include "shared-bindings/busio/UART.h"
#include "mpconfigport.h"
#include "py/gc.h"
#include "py/mperrno.h"
#include "py/nlr.h"
#include "py/runtime.h"
#include "py/stream.h"
#include "samd21_pins.h"
#include "tick.h"
#include "asf/sam0/drivers/sercom/sercom_interrupt.h"
#undef ENABLE
busio_uart_obj_t *_uart_instances[SERCOM_INST_NUM];
static void _sercom_default_handler(
const uint8_t instance)
{
Assert(false);
}
static void _busio_uart_interrupt_handler(uint8_t instance)
{
/* Temporary variables */
uint16_t interrupt_status;
uint8_t error_code;
/* Get device instance from the look-up table */
struct usart_module *module
= (struct usart_module *)_sercom_instances[instance];
busio_uart_obj_t *self = _uart_instances[instance];
/* Pointer to the hardware module instance */
SercomUsart *const usart_hw = &(module->hw->USART);
/* Wait for the synchronization to complete */
_usart_wait_for_sync(module);
/* Read and mask interrupt flag register */
interrupt_status = usart_hw->INTFLAG.reg;
interrupt_status &= usart_hw->INTENSET.reg;
/* Check if the Receive Complete interrupt has occurred, and that
* there's more data to receive */
if (interrupt_status & SERCOM_USART_INTFLAG_RXC) {
/* Read out the status code and mask away all but the 4 LSBs*/
error_code = (uint8_t)(usart_hw->STATUS.reg & SERCOM_USART_STATUS_MASK);
/* CTS status should not be considered as an error */
if(error_code & SERCOM_USART_STATUS_CTS) {
error_code &= ~SERCOM_USART_STATUS_CTS;
}
/* Check if an error has occurred during the receiving */
if (error_code) {
/* Check which error occurred */
if (error_code & SERCOM_USART_STATUS_FERR) {
/* Store the error code and clear flag by writing 1 to it */
usart_hw->STATUS.reg = SERCOM_USART_STATUS_FERR;
} else if (error_code & SERCOM_USART_STATUS_BUFOVF) {
/* Store the error code and clear flag by writing 1 to it */
usart_hw->STATUS.reg = SERCOM_USART_STATUS_BUFOVF;
} else if (error_code & SERCOM_USART_STATUS_PERR) {
/* Store the error code and clear flag by writing 1 to it */
usart_hw->STATUS.reg = SERCOM_USART_STATUS_PERR;
}
self->rx_error = true;
} else {
/* Read current packet from DATA register,
* increment buffer pointer and decrement buffer length */
uint16_t received_data = (usart_hw->DATA.reg & SERCOM_USART_DATA_MASK);
common_hal_mcu_disable_interrupts();
/* Read value will be at least 8-bits long */
uint32_t buffer_end = (self->buffer_start + self->buffer_size) % self->buffer_length;
self->buffer[buffer_end] = received_data;
self->buffer_size++;
if (module->character_size == USART_CHARACTER_SIZE_9BIT) {
buffer_end = (self->buffer_start + self->buffer_size) % self->buffer_length;
/* 9-bit data, write next received byte to the buffer */
self->buffer[buffer_end] = (received_data >> 8);
self->buffer_size++;
}
if (self->buffer_size > self->buffer_length) {
self->buffer_start++;
if (module->character_size == USART_CHARACTER_SIZE_9BIT) {
self->buffer_start++;
}
self->buffer_size = self->buffer_length;
}
common_hal_mcu_enable_interrupts();
}
}
}
void common_hal_busio_uart_construct(busio_uart_obj_t *self,
const mcu_pin_obj_t * tx, const mcu_pin_obj_t * rx, uint32_t baudrate,
uint8_t bits, uart_parity_t parity, uint8_t stop, uint32_t timeout,
uint8_t receiver_buffer_size) {
Sercom* sercom = NULL;
uint32_t rx_pinmux = PINMUX_UNUSED;
uint8_t rx_pad = 5; // Unset pad
uint32_t tx_pinmux = PINMUX_UNUSED;
uint8_t tx_pad = 5; // Unset pad
for (int i = 0; i < NUM_SERCOMS_PER_PIN; i++) {
Sercom* potential_sercom = NULL;
if (tx != NULL) {
potential_sercom = tx->sercom[i].sercom;
if (potential_sercom == NULL ||
potential_sercom->I2CM.CTRLA.bit.ENABLE != 0 ||
!(tx->sercom[i].pad == 0 ||
tx->sercom[i].pad == 2)) {
continue;
}
tx_pinmux = PINMUX(tx->pin, (i == 0) ? MUX_C : MUX_D);
tx_pad = tx->sercom[i].pad;
if (rx == NULL) {
sercom = potential_sercom;
break;
}
}
for (int j = 0; j < NUM_SERCOMS_PER_PIN; j++) {
if (((tx == NULL && rx->sercom[j].sercom->I2CM.CTRLA.bit.ENABLE == 0) ||
potential_sercom == rx->sercom[j].sercom) &&
rx->sercom[j].pad != tx_pad) {
rx_pinmux = PINMUX(rx->pin, (j == 0) ? MUX_C : MUX_D);
rx_pad = rx->sercom[j].pad;
sercom = rx->sercom[j].sercom;
break;
}
}
if (sercom != NULL) {
break;
}
}
if (sercom == NULL) {
mp_raise_ValueError("Invalid pins");
}
if (tx == NULL) {
tx_pad = 0;
if (rx_pad == 0) {
tx_pad = 2;
}
}
if (rx == NULL) {
rx_pad = (tx_pad + 1) % 4;
}
struct usart_config config_usart;
usart_get_config_defaults(&config_usart);
config_usart.mux_setting = (SERCOM_USART_CTRLA_RXPO(rx_pad) | SERCOM_USART_CTRLA_TXPO(tx_pad / 2));
if (parity == PARITY_ODD) {
config_usart.parity = USART_PARITY_ODD;
} else if (parity == PARITY_EVEN) {
config_usart.parity = USART_PARITY_EVEN;
}
config_usart.stopbits = stop - 1;
config_usart.character_size = bits % 8;
config_usart.baudrate = baudrate;
// Map pad to pinmux through a short array.
uint32_t *pinmuxes[4] = {&config_usart.pinmux_pad0,
&config_usart.pinmux_pad1,
&config_usart.pinmux_pad2,
&config_usart.pinmux_pad3};
// Pin muxes have a default pin, set them to unused so that no other pins are changed.
for (int i = 0; i < 4; i++) {
*pinmuxes[i] = PINMUX_UNUSED;
}
self->rx_pin = NO_PIN;
config_usart.receiver_enable = rx != NULL;
if (rx != NULL) {
*pinmuxes[rx_pad] = rx_pinmux;
self->rx_pin = rx->pin;
claim_pin(rx);
}
self->tx_pin = NO_PIN;
config_usart.transmitter_enable = tx != NULL;
if (tx != NULL) {
*pinmuxes[tx_pad] = tx_pinmux;
self->tx_pin = tx->pin;
claim_pin(tx);
}
self->timeout_ms = timeout;
self->buffer_length = receiver_buffer_size;
self->buffer_length *= (bits + 7) / 8;
self->buffer = (uint8_t *) gc_alloc(self->buffer_length * sizeof(uint8_t), false);
if (self->buffer == NULL) {
common_hal_busio_uart_deinit(self);
mp_raise_msg(&mp_type_MemoryError, "Failed to allocate RX buffer");
}
if (usart_init(&self->uart_instance, sercom, &config_usart) != STATUS_OK) {
common_hal_busio_uart_deinit(self);
mp_raise_OSError(MP_EIO);
}
// We use our own interrupt handler because we want a circular buffer
// instead of the jobs that ASF provides.
uint8_t instance_index = _sercom_get_sercom_inst_index(self->uart_instance.hw);
_sercom_set_handler(instance_index, _busio_uart_interrupt_handler);
_sercom_instances[instance_index] = &self->uart_instance;
_uart_instances[instance_index] = self;
/* Enable Global interrupt for module */
system_interrupt_enable(_sercom_get_interrupt_vector(self->uart_instance.hw));
usart_enable(&self->uart_instance);
self->uart_instance.hw->USART.INTENSET.bit.RXC = true;
}
bool common_hal_busio_uart_deinited(busio_uart_obj_t *self) {
return self->rx_pin == NO_PIN && self->tx_pin == NO_PIN;
}
void common_hal_busio_uart_deinit(busio_uart_obj_t *self) {
if (common_hal_busio_uart_deinited(self)) {
return;
}
self->uart_instance.hw->USART.INTENCLR.bit.RXC = true;
uint8_t instance_index = _sercom_get_sercom_inst_index(self->uart_instance.hw);
_sercom_set_handler(instance_index, &_sercom_default_handler);
_sercom_instances[instance_index] = NULL;
_uart_instances[instance_index] = NULL;
system_interrupt_disable(_sercom_get_interrupt_vector(self->uart_instance.hw));
usart_disable(&self->uart_instance);
reset_pin(self->rx_pin);
reset_pin(self->tx_pin);
self->rx_pin = NO_PIN;
self->tx_pin = NO_PIN;
}
// Read characters.
size_t common_hal_busio_uart_read(busio_uart_obj_t *self, uint8_t *data, size_t len, int *errcode) {
size_t total_read = 0;
uint64_t start_ticks = ticks_ms;
while (total_read < len && ticks_ms - start_ticks < self->timeout_ms) {
if (self->buffer_size > 0) {
common_hal_mcu_disable_interrupts();
data[total_read] = self->buffer[self->buffer_start];
if (self->uart_instance.character_size == USART_CHARACTER_SIZE_9BIT) {
data[total_read + 1] = self->buffer[self->buffer_start + 1];
self->buffer_start += 2;
self->buffer_size -= 2;
} else {
self->buffer_start++;
self->buffer_size--;
}
self->buffer_start = self->buffer_start % self->buffer_length;
common_hal_mcu_enable_interrupts();
// Reset the timeout every character read.
total_read++;
start_ticks = ticks_ms;
}
#ifdef MICROPY_VM_HOOK_LOOP
MICROPY_VM_HOOK_LOOP
#endif
}
if (total_read == 0) {
*errcode = MP_EAGAIN;
return MP_STREAM_ERROR;
}
return total_read;
}
// Write characters.
size_t common_hal_busio_uart_write(busio_uart_obj_t *self, const uint8_t *data, size_t len, int *errcode) {
/* Check that the transmitter is enabled */
if (!(self->uart_instance.transmitter_enabled)) {
*errcode = MP_EIO;
return MP_STREAM_ERROR;
}
/* Get a pointer to the hardware module instance */
SercomUsart *const usart_hw = &(self->uart_instance.hw->USART);
/* Wait until synchronization is complete */
_usart_wait_for_sync(&self->uart_instance);
uint16_t tx_pos = 0;
bool ok = true;
uint64_t start_ticks = 0;
/* Blocks while buffer is being transferred */
while (len--) {
/* Wait for the USART to be ready for new data and abort
* operation if it doesn't get ready within the timeout*/
ok = false;
start_ticks = ticks_ms;
while (ticks_ms - start_ticks < self->timeout_ms) {
if (usart_hw->INTFLAG.reg & SERCOM_USART_INTFLAG_DRE) {
ok = true;
break;
}
#ifdef MICROPY_VM_HOOK_LOOP
MICROPY_VM_HOOK_LOOP
#endif
}
if (!ok) {
break;
}
/* Data to send is at least 8 bits long */
uint16_t data_to_send = data[tx_pos++];
/* Check if the character size exceeds 8 bit */
if (self->uart_instance.character_size == USART_CHARACTER_SIZE_9BIT) {
data_to_send |= (data[tx_pos++] << 8);
}
/* Send the data through the USART module */
enum status_code status = usart_write_wait(&self->uart_instance, data_to_send);
if (status != STATUS_OK) {
ok = false;
}
}
/* Wait until Transmit is complete or timeout */
if (ok) {
ok = false;
start_ticks = ticks_ms;
while (ticks_ms - start_ticks < self->timeout_ms) {
if (usart_hw->INTFLAG.reg & SERCOM_USART_INTFLAG_TXC) {
ok = true;
break;
}
#ifdef MICROPY_VM_HOOK_LOOP
MICROPY_VM_HOOK_LOOP
#endif
}
}
if (!ok && tx_pos == 0) {
*errcode = MP_EAGAIN;
return MP_STREAM_ERROR;
}
return tx_pos;
}
uint32_t common_hal_busio_uart_rx_characters_available(busio_uart_obj_t *self) {
if (self->uart_instance.character_size == USART_CHARACTER_SIZE_9BIT) {
return self->buffer_size / 2;
}
return self->buffer_size;
}
bool common_hal_busio_uart_ready_to_tx(busio_uart_obj_t *self) {
if (!(self->uart_instance.transmitter_enabled)) {
return false;
}
return self->uart_instance.hw->USART.INTFLAG.bit.DRE;
}