392 lines
14 KiB
C
392 lines
14 KiB
C
/*
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* This file is part of the MicroPython project, http://micropython.org/
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*
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* The MIT License (MIT)
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*
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* Copyright (c) 2016 Damien P. George
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#include "shared-bindings/microcontroller/__init__.h"
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#include "shared-bindings/busio/UART.h"
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#include "mpconfigport.h"
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#include "py/gc.h"
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#include "py/mperrno.h"
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#include "py/nlr.h"
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#include "py/runtime.h"
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#include "py/stream.h"
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#include "samd21_pins.h"
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#include "tick.h"
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#include "asf/sam0/drivers/sercom/sercom_interrupt.h"
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#undef ENABLE
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busio_uart_obj_t *_uart_instances[SERCOM_INST_NUM];
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static void _sercom_default_handler(
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const uint8_t instance)
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{
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Assert(false);
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}
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static void _busio_uart_interrupt_handler(uint8_t instance)
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{
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/* Temporary variables */
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uint16_t interrupt_status;
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uint8_t error_code;
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/* Get device instance from the look-up table */
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struct usart_module *module
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= (struct usart_module *)_sercom_instances[instance];
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busio_uart_obj_t *self = _uart_instances[instance];
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/* Pointer to the hardware module instance */
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SercomUsart *const usart_hw = &(module->hw->USART);
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/* Wait for the synchronization to complete */
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_usart_wait_for_sync(module);
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/* Read and mask interrupt flag register */
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interrupt_status = usart_hw->INTFLAG.reg;
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interrupt_status &= usart_hw->INTENSET.reg;
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/* Check if the Receive Complete interrupt has occurred, and that
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* there's more data to receive */
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if (interrupt_status & SERCOM_USART_INTFLAG_RXC) {
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/* Read out the status code and mask away all but the 4 LSBs*/
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error_code = (uint8_t)(usart_hw->STATUS.reg & SERCOM_USART_STATUS_MASK);
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/* CTS status should not be considered as an error */
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if(error_code & SERCOM_USART_STATUS_CTS) {
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error_code &= ~SERCOM_USART_STATUS_CTS;
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}
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/* Check if an error has occurred during the receiving */
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if (error_code) {
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/* Check which error occurred */
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if (error_code & SERCOM_USART_STATUS_FERR) {
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/* Store the error code and clear flag by writing 1 to it */
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usart_hw->STATUS.reg = SERCOM_USART_STATUS_FERR;
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} else if (error_code & SERCOM_USART_STATUS_BUFOVF) {
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/* Store the error code and clear flag by writing 1 to it */
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usart_hw->STATUS.reg = SERCOM_USART_STATUS_BUFOVF;
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} else if (error_code & SERCOM_USART_STATUS_PERR) {
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/* Store the error code and clear flag by writing 1 to it */
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usart_hw->STATUS.reg = SERCOM_USART_STATUS_PERR;
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}
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self->rx_error = true;
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} else {
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/* Read current packet from DATA register,
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* increment buffer pointer and decrement buffer length */
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uint16_t received_data = (usart_hw->DATA.reg & SERCOM_USART_DATA_MASK);
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common_hal_mcu_disable_interrupts();
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/* Read value will be at least 8-bits long */
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uint32_t buffer_end = (self->buffer_start + self->buffer_size) % self->buffer_length;
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self->buffer[buffer_end] = received_data;
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self->buffer_size++;
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if (module->character_size == USART_CHARACTER_SIZE_9BIT) {
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buffer_end = (self->buffer_start + self->buffer_size) % self->buffer_length;
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/* 9-bit data, write next received byte to the buffer */
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self->buffer[buffer_end] = (received_data >> 8);
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self->buffer_size++;
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}
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if (self->buffer_size > self->buffer_length) {
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self->buffer_start++;
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if (module->character_size == USART_CHARACTER_SIZE_9BIT) {
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self->buffer_start++;
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}
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self->buffer_size = self->buffer_length;
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}
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common_hal_mcu_enable_interrupts();
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}
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}
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}
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void common_hal_busio_uart_construct(busio_uart_obj_t *self,
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const mcu_pin_obj_t * tx, const mcu_pin_obj_t * rx, uint32_t baudrate,
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uint8_t bits, uart_parity_t parity, uint8_t stop, uint32_t timeout,
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uint8_t receiver_buffer_size) {
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Sercom* sercom = NULL;
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uint32_t rx_pinmux = PINMUX_UNUSED;
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uint8_t rx_pad = 5; // Unset pad
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uint32_t tx_pinmux = PINMUX_UNUSED;
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uint8_t tx_pad = 5; // Unset pad
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for (int i = 0; i < NUM_SERCOMS_PER_PIN; i++) {
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Sercom* potential_sercom = NULL;
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if (tx != NULL) {
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potential_sercom = tx->sercom[i].sercom;
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if (potential_sercom == NULL ||
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potential_sercom->I2CM.CTRLA.bit.ENABLE != 0 ||
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!(tx->sercom[i].pad == 0 ||
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tx->sercom[i].pad == 2)) {
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continue;
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}
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tx_pinmux = PINMUX(tx->pin, (i == 0) ? MUX_C : MUX_D);
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tx_pad = tx->sercom[i].pad;
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if (rx == NULL) {
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sercom = potential_sercom;
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break;
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}
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}
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for (int j = 0; j < NUM_SERCOMS_PER_PIN; j++) {
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if (((tx == NULL && rx->sercom[j].sercom->I2CM.CTRLA.bit.ENABLE == 0) ||
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potential_sercom == rx->sercom[j].sercom) &&
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rx->sercom[j].pad != tx_pad) {
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rx_pinmux = PINMUX(rx->pin, (j == 0) ? MUX_C : MUX_D);
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rx_pad = rx->sercom[j].pad;
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sercom = rx->sercom[j].sercom;
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break;
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}
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}
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if (sercom != NULL) {
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break;
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}
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}
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if (sercom == NULL) {
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mp_raise_ValueError("Invalid pins");
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}
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if (tx == NULL) {
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tx_pad = 0;
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if (rx_pad == 0) {
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tx_pad = 2;
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}
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}
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if (rx == NULL) {
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rx_pad = (tx_pad + 1) % 4;
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}
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struct usart_config config_usart;
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usart_get_config_defaults(&config_usart);
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config_usart.mux_setting = (SERCOM_USART_CTRLA_RXPO(rx_pad) | SERCOM_USART_CTRLA_TXPO(tx_pad / 2));
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if (parity == PARITY_ODD) {
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config_usart.parity = USART_PARITY_ODD;
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} else if (parity == PARITY_EVEN) {
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config_usart.parity = USART_PARITY_EVEN;
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}
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config_usart.stopbits = stop - 1;
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config_usart.character_size = bits % 8;
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config_usart.baudrate = baudrate;
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// Map pad to pinmux through a short array.
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uint32_t *pinmuxes[4] = {&config_usart.pinmux_pad0,
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&config_usart.pinmux_pad1,
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&config_usart.pinmux_pad2,
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&config_usart.pinmux_pad3};
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// Pin muxes have a default pin, set them to unused so that no other pins are changed.
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for (int i = 0; i < 4; i++) {
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*pinmuxes[i] = PINMUX_UNUSED;
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}
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self->rx_pin = NO_PIN;
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config_usart.receiver_enable = rx != NULL;
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if (rx != NULL) {
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*pinmuxes[rx_pad] = rx_pinmux;
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self->rx_pin = rx->pin;
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claim_pin(rx);
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}
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self->tx_pin = NO_PIN;
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config_usart.transmitter_enable = tx != NULL;
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if (tx != NULL) {
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*pinmuxes[tx_pad] = tx_pinmux;
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self->tx_pin = tx->pin;
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claim_pin(tx);
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}
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self->timeout_ms = timeout;
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self->buffer_length = receiver_buffer_size;
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self->buffer_length *= (bits + 7) / 8;
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self->buffer = (uint8_t *) gc_alloc(self->buffer_length * sizeof(uint8_t), false);
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if (self->buffer == NULL) {
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common_hal_busio_uart_deinit(self);
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mp_raise_msg(&mp_type_MemoryError, "Failed to allocate RX buffer");
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}
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if (usart_init(&self->uart_instance, sercom, &config_usart) != STATUS_OK) {
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common_hal_busio_uart_deinit(self);
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mp_raise_OSError(MP_EIO);
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}
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// We use our own interrupt handler because we want a circular buffer
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// instead of the jobs that ASF provides.
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uint8_t instance_index = _sercom_get_sercom_inst_index(self->uart_instance.hw);
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_sercom_set_handler(instance_index, _busio_uart_interrupt_handler);
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_sercom_instances[instance_index] = &self->uart_instance;
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_uart_instances[instance_index] = self;
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/* Enable Global interrupt for module */
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system_interrupt_enable(_sercom_get_interrupt_vector(self->uart_instance.hw));
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usart_enable(&self->uart_instance);
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self->uart_instance.hw->USART.INTENSET.bit.RXC = true;
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}
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bool common_hal_busio_uart_deinited(busio_uart_obj_t *self) {
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return self->rx_pin == NO_PIN && self->tx_pin == NO_PIN;
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}
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void common_hal_busio_uart_deinit(busio_uart_obj_t *self) {
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if (common_hal_busio_uart_deinited(self)) {
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return;
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}
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self->uart_instance.hw->USART.INTENCLR.bit.RXC = true;
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uint8_t instance_index = _sercom_get_sercom_inst_index(self->uart_instance.hw);
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_sercom_set_handler(instance_index, &_sercom_default_handler);
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_sercom_instances[instance_index] = NULL;
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_uart_instances[instance_index] = NULL;
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system_interrupt_disable(_sercom_get_interrupt_vector(self->uart_instance.hw));
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usart_disable(&self->uart_instance);
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reset_pin(self->rx_pin);
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reset_pin(self->tx_pin);
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self->rx_pin = NO_PIN;
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self->tx_pin = NO_PIN;
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}
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// Read characters.
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size_t common_hal_busio_uart_read(busio_uart_obj_t *self, uint8_t *data, size_t len, int *errcode) {
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size_t total_read = 0;
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uint64_t start_ticks = ticks_ms;
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while (total_read < len && ticks_ms - start_ticks < self->timeout_ms) {
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if (self->buffer_size > 0) {
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common_hal_mcu_disable_interrupts();
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data[total_read] = self->buffer[self->buffer_start];
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if (self->uart_instance.character_size == USART_CHARACTER_SIZE_9BIT) {
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data[total_read + 1] = self->buffer[self->buffer_start + 1];
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self->buffer_start += 2;
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self->buffer_size -= 2;
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} else {
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self->buffer_start++;
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self->buffer_size--;
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}
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self->buffer_start = self->buffer_start % self->buffer_length;
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common_hal_mcu_enable_interrupts();
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// Reset the timeout every character read.
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total_read++;
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start_ticks = ticks_ms;
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}
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#ifdef MICROPY_VM_HOOK_LOOP
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MICROPY_VM_HOOK_LOOP
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#endif
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}
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if (total_read == 0) {
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*errcode = MP_EAGAIN;
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return MP_STREAM_ERROR;
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}
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return total_read;
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}
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// Write characters.
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size_t common_hal_busio_uart_write(busio_uart_obj_t *self, const uint8_t *data, size_t len, int *errcode) {
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/* Check that the transmitter is enabled */
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if (!(self->uart_instance.transmitter_enabled)) {
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*errcode = MP_EIO;
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return MP_STREAM_ERROR;
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}
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/* Get a pointer to the hardware module instance */
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SercomUsart *const usart_hw = &(self->uart_instance.hw->USART);
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/* Wait until synchronization is complete */
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_usart_wait_for_sync(&self->uart_instance);
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uint16_t tx_pos = 0;
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bool ok = true;
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uint64_t start_ticks = 0;
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/* Blocks while buffer is being transferred */
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while (len--) {
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/* Wait for the USART to be ready for new data and abort
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* operation if it doesn't get ready within the timeout*/
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ok = false;
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start_ticks = ticks_ms;
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while (ticks_ms - start_ticks < self->timeout_ms) {
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if (usart_hw->INTFLAG.reg & SERCOM_USART_INTFLAG_DRE) {
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ok = true;
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break;
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}
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#ifdef MICROPY_VM_HOOK_LOOP
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MICROPY_VM_HOOK_LOOP
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#endif
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}
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if (!ok) {
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break;
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}
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/* Data to send is at least 8 bits long */
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uint16_t data_to_send = data[tx_pos++];
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/* Check if the character size exceeds 8 bit */
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if (self->uart_instance.character_size == USART_CHARACTER_SIZE_9BIT) {
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data_to_send |= (data[tx_pos++] << 8);
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}
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/* Send the data through the USART module */
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enum status_code status = usart_write_wait(&self->uart_instance, data_to_send);
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if (status != STATUS_OK) {
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ok = false;
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}
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}
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/* Wait until Transmit is complete or timeout */
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if (ok) {
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ok = false;
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start_ticks = ticks_ms;
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while (ticks_ms - start_ticks < self->timeout_ms) {
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if (usart_hw->INTFLAG.reg & SERCOM_USART_INTFLAG_TXC) {
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ok = true;
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break;
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}
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#ifdef MICROPY_VM_HOOK_LOOP
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MICROPY_VM_HOOK_LOOP
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#endif
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}
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}
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if (!ok && tx_pos == 0) {
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*errcode = MP_EAGAIN;
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return MP_STREAM_ERROR;
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}
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return tx_pos;
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}
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uint32_t common_hal_busio_uart_rx_characters_available(busio_uart_obj_t *self) {
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if (self->uart_instance.character_size == USART_CHARACTER_SIZE_9BIT) {
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return self->buffer_size / 2;
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}
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return self->buffer_size;
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}
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bool common_hal_busio_uart_ready_to_tx(busio_uart_obj_t *self) {
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if (!(self->uart_instance.transmitter_enabled)) {
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return false;
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}
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return self->uart_instance.hw->USART.INTFLAG.bit.DRE;
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}
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