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/*
* 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 "lib/utils/interrupt_char.h"
#include "py/gc.h"
#include "py/mperrno.h"
#include "py/runtime.h"
#include "py/stream.h"
#include "supervisor/shared/translate.h"
#include "supervisor/shared/tick.h"
#include "hpl_sercom_config.h"
#include "peripheral_clk_config.h"
#include "hal/include/hal_gpio.h"
#include "hal/include/hal_usart_async.h"
#include "hal/include/hpl_usart_async.h"
#include "samd/sercom.h"
// Do-nothing callback needed so that usart_async code will enable rx interrupts.
// See comment below re usart_async_register_callback()
static void usart_async_rxc_callback(const struct usart_async_descriptor *const descr) {
// Nothing needs to be done by us.
}
void common_hal_busio_uart_construct(busio_uart_obj_t *self,
const mcu_pin_obj_t * tx, const mcu_pin_obj_t * rx,
const mcu_pin_obj_t * rts, const mcu_pin_obj_t * cts,
const mcu_pin_obj_t * rs485_dir, bool rs485_invert,
uint32_t baudrate, uint8_t bits, uart_parity_t parity, uint8_t stop,
mp_float_t timeout, uint16_t receiver_buffer_size) {
Sercom* sercom = NULL;
uint8_t sercom_index = 255; // Unset index
uint32_t rx_pinmux = 0;
uint8_t rx_pad = 255; // Unset pad
uint32_t tx_pinmux = 0;
uint8_t tx_pad = 255; // Unset pad
if ((rts != NULL) || (cts != NULL) || (rs485_dir != NULL) || (rs485_invert)) {
mp_raise_ValueError(translate("RTS/CTS/RS485 Not yet supported on this device"));
}
if (bits > 8) {
mp_raise_NotImplementedError(translate("bytes > 8 bits not supported"));
}
bool have_tx = tx != NULL;
bool have_rx = rx != NULL;
if (!have_tx && !have_rx) {
mp_raise_ValueError(translate("tx and rx cannot both be None"));
}
self->baudrate = baudrate;
self->character_bits = bits;
self->timeout_ms = timeout * 1000;
// This assignment is only here because the usart_async routines take a *const argument.
struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
for (int i = 0; i < NUM_SERCOMS_PER_PIN; i++) {
Sercom* potential_sercom = NULL;
if (have_tx) {
sercom_index = tx->sercom[i].index;
if (sercom_index >= SERCOM_INST_NUM) {
continue;
}
potential_sercom = sercom_insts[sercom_index];
#ifdef SAMD21
if (potential_sercom->USART.CTRLA.bit.ENABLE != 0 ||
!(tx->sercom[i].pad == 0 ||
tx->sercom[i].pad == 2)) {
continue;
}
#endif
#ifdef SAMD51
if (potential_sercom->USART.CTRLA.bit.ENABLE != 0 ||
!(tx->sercom[i].pad == 0)) {
continue;
}
#endif
tx_pinmux = PINMUX(tx->number, (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 (((!have_tx && rx->sercom[j].index < SERCOM_INST_NUM &&
sercom_insts[rx->sercom[j].index]->USART.CTRLA.bit.ENABLE == 0) ||
sercom_index == rx->sercom[j].index) &&
rx->sercom[j].pad != tx_pad) {
rx_pinmux = PINMUX(rx->number, (j == 0) ? MUX_C : MUX_D);
rx_pad = rx->sercom[j].pad;
sercom = sercom_insts[rx->sercom[j].index];
sercom_index = rx->sercom[j].index;
break;
}
}
if (sercom != NULL) {
break;
}
}
if (sercom == NULL) {
mp_raise_ValueError(translate("Invalid pins"));
}
if (!have_tx) {
tx_pad = 0;
if (rx_pad == 0) {
tx_pad = 2;
}
}
if (!have_rx) {
rx_pad = (tx_pad + 1) % 4;
}
// Set up clocks on SERCOM.
samd_peripherals_sercom_clock_init(sercom, sercom_index);
if (rx && receiver_buffer_size > 0) {
self->buffer_length = receiver_buffer_size;
// Initially allocate the UART's buffer in the long-lived part of the
// heap. UARTs are generally long-lived objects, but the "make long-
// lived" machinery is incapable of moving internal pointers like
// self->buffer, so do it manually. (However, as long as internal
// pointers like this are NOT moved, allocating the buffer
// in the long-lived pool is not strictly necessary)
self->buffer = (uint8_t *) gc_alloc(self->buffer_length * sizeof(uint8_t), false, true);
if (self->buffer == NULL) {
common_hal_busio_uart_deinit(self);
mp_raise_msg_varg(&mp_type_MemoryError, translate("Failed to allocate RX buffer of %d bytes"), self->buffer_length * sizeof(uint8_t));
}
} else {
self->buffer_length = 0;
self->buffer = NULL;
}
if (usart_async_init(usart_desc_p, sercom, self->buffer, self->buffer_length, NULL) != ERR_NONE) {
mp_raise_ValueError(translate("Could not initialize UART"));
}
// usart_async_init() sets a number of defaults based on a prototypical SERCOM
// which don't necessarily match what we need. After calling it, set the values
// specific to this instantiation of UART.
// Set pads computed for this SERCOM.
// TXPO:
// 0x0: TX pad 0; no RTS/CTS
// 0x1: TX pad 2; no RTS/CTS
// 0x2: TX pad 0; RTS: pad 2, CTS: pad 3 (not used by us right now)
// So divide by 2 to map pad to value.
// RXPO:
// 0x0: RX pad 0
// 0x1: RX pad 1
// 0x2: RX pad 2
// 0x3: RX pad 3
// Doing a group mask and set of the registers saves 60 bytes over setting the bitfields individually.
sercom->USART.CTRLA.reg &= ~(SERCOM_USART_CTRLA_TXPO_Msk |
SERCOM_USART_CTRLA_RXPO_Msk |
SERCOM_USART_CTRLA_FORM_Msk);
sercom->USART.CTRLA.reg |= SERCOM_USART_CTRLA_TXPO(tx_pad / 2) |
SERCOM_USART_CTRLA_RXPO(rx_pad) |
(parity == PARITY_NONE ? 0 : SERCOM_USART_CTRLA_FORM(1));
// Enable tx and/or rx based on whether the pins were specified.
// CHSIZE is 0 for 8 bits, 5, 6, 7 for 5, 6, 7 bits. 1 for 9 bits, but we don't support that.
sercom->USART.CTRLB.reg &= ~(SERCOM_USART_CTRLB_TXEN |
SERCOM_USART_CTRLB_RXEN |
SERCOM_USART_CTRLB_PMODE |
SERCOM_USART_CTRLB_SBMODE |
SERCOM_USART_CTRLB_CHSIZE_Msk);
sercom->USART.CTRLB.reg |= (have_tx ? SERCOM_USART_CTRLB_TXEN : 0) |
(have_rx ? SERCOM_USART_CTRLB_RXEN : 0) |
(parity == PARITY_ODD ? SERCOM_USART_CTRLB_PMODE : 0) |
(stop > 1 ? SERCOM_USART_CTRLB_SBMODE : 0) |
SERCOM_USART_CTRLB_CHSIZE(bits % 8);
// Set baud rate
common_hal_busio_uart_set_baudrate(self, baudrate);
// Turn on rx interrupt handling. The UART async driver has its own set of internal callbacks,
// which are set up by uart_async_init(). These in turn can call user-specified callbacks.
// In fact, the actual interrupts are not enabled unless we set up a user-specified callback.
// This is confusing. It's explained in the Atmel START User Guide -> Implementation Description ->
// Different read function behavior in some asynchronous drivers. As of this writing:
// http://start.atmel.com/static/help/index.html?GUID-79201A5A-226F-4FBB-B0B8-AB0BE0554836
// Look at the ASFv4 code example for async USART.
usart_async_register_callback(usart_desc_p, USART_ASYNC_RXC_CB, usart_async_rxc_callback);
if (have_tx) {
gpio_set_pin_direction(tx->number, GPIO_DIRECTION_OUT);
gpio_set_pin_pull_mode(tx->number, GPIO_PULL_OFF);
gpio_set_pin_function(tx->number, tx_pinmux);
self->tx_pin = tx->number;
claim_pin(tx);
} else {
self->tx_pin = NO_PIN;
}
if (have_rx) {
gpio_set_pin_direction(rx->number, GPIO_DIRECTION_IN);
gpio_set_pin_pull_mode(rx->number, GPIO_PULL_OFF);
gpio_set_pin_function(rx->number, rx_pinmux);
self->rx_pin = rx->number;
claim_pin(rx);
} else {
self->rx_pin = NO_PIN;
}
usart_async_enable(usart_desc_p);
}
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;
}
// This assignment is only here because the usart_async routines take a *const argument.
struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
usart_async_disable(usart_desc_p);
usart_async_deinit(usart_desc_p);
reset_pin_number(self->rx_pin);
reset_pin_number(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) {
if (self->rx_pin == NO_PIN) {
mp_raise_ValueError(translate("No RX pin"));
}
// This assignment is only here because the usart_async routines take a *const argument.
struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
if (len == 0) {
// Nothing to read.
return 0;
}
struct io_descriptor *io;
usart_async_get_io_descriptor(usart_desc_p, &io);
size_t total_read = 0;
uint64_t start_ticks = supervisor_ticks_ms64();
// Busy-wait until timeout or until we've read enough chars.
while (supervisor_ticks_ms64() - start_ticks <= self->timeout_ms) {
// Read as many chars as we can right now, up to len.
size_t num_read = io_read(io, data, len);
// Advance pointer in data buffer, and decrease how many chars left to read.
data += num_read;
len -= num_read;
total_read += num_read;
if (len == 0) {
// Don't need to read any more: data buf is full.
break;
}
if (num_read > 0) {
// Reset the timeout on every character read.
start_ticks = supervisor_ticks_ms64();
}
RUN_BACKGROUND_TASKS;
// Allow user to break out of a timeout with a KeyboardInterrupt.
if (mp_hal_is_interrupted()) {
break;
}
// If we are zero timeout, make sure we don't loop again (in the event
// we read in under 1ms)
if (self->timeout_ms == 0) {
break;
}
}
if (total_read == 0) {
*errcode = 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) {
if (self->tx_pin == NO_PIN) {
mp_raise_ValueError(translate("No TX pin"));
}
// This assignment is only here because the usart_async routines take a *const argument.
struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
struct io_descriptor *io;
usart_async_get_io_descriptor(usart_desc_p, &io);
// Start writing characters. This is non-blocking and will
// return immediately after setting up the write.
if (io_write(io, data, len) < 0) {
*errcode = MP_EAGAIN;
return MP_STREAM_ERROR;
}
// Busy-wait until all characters transmitted.
struct usart_async_status async_status;
while (true) {
usart_async_get_status(usart_desc_p, &async_status);
if (async_status.txcnt >= len) {
break;
}
RUN_BACKGROUND_TASKS;
}
return len;
}
uint32_t common_hal_busio_uart_get_baudrate(busio_uart_obj_t *self) {
return self->baudrate;
}
void common_hal_busio_uart_set_baudrate(busio_uart_obj_t *self, uint32_t baudrate) {
// This assignment is only here because the usart_async routines take a *const argument.
struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
usart_async_set_baud_rate(usart_desc_p,
// Samples and ARITHMETIC vs FRACTIONAL must correspond to USART_SAMPR in
// hpl_sercom_config.h.
_usart_async_calculate_baud_rate(baudrate, // e.g. 9600 baud
PROTOTYPE_SERCOM_USART_ASYNC_CLOCK_FREQUENCY,
16, // samples
USART_BAUDRATE_ASYNCH_ARITHMETIC,
0 // fraction - not used for ARITHMETIC
));
self->baudrate = baudrate;
}
mp_float_t common_hal_busio_uart_get_timeout(busio_uart_obj_t *self) {
return (mp_float_t) (self->timeout_ms / 1000.0f);
}
void common_hal_busio_uart_set_timeout(busio_uart_obj_t *self, mp_float_t timeout) {
self->timeout_ms = timeout * 1000;
}
uint32_t common_hal_busio_uart_rx_characters_available(busio_uart_obj_t *self) {
// This assignment is only here because the usart_async routines take a *const argument.
struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
struct usart_async_status async_status;
usart_async_get_status(usart_desc_p, &async_status);
return async_status.rxcnt;
}
void common_hal_busio_uart_clear_rx_buffer(busio_uart_obj_t *self) {
// This assignment is only here because the usart_async routines take a *const argument.
struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
usart_async_flush_rx_buffer(usart_desc_p);
}
// True if there are no characters still to be written.
bool common_hal_busio_uart_ready_to_tx(busio_uart_obj_t *self) {
if (self->tx_pin == NO_PIN) {
return false;
}
// This assignment is only here because the usart_async routines take a *const argument.
struct usart_async_descriptor * const usart_desc_p = (struct usart_async_descriptor * const) &self->usart_desc;
struct usart_async_status async_status;
usart_async_get_status(usart_desc_p, &async_status);
return !(async_status.flags & USART_ASYNC_STATUS_BUSY);
}