mirror of
https://github.com/portapack-mayhem/mayhem-firmware.git
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290 lines
9.6 KiB
C
Executable File
290 lines
9.6 KiB
C
Executable File
/*
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ChibiOS/RT - Copyright (C) 2006-2013 Giovanni Di Sirio
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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/**
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* @file AVR/i2c_lld.c
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* @brief AVR I2C subsystem low level driver source.
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*
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* @addtogroup I2C
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* @{
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*/
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#include "ch.h"
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#include "hal.h"
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#if HAL_USE_I2C || defined(__DOXYGEN__)
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/*===========================================================================*/
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/* Driver local definitions. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver exported variables. */
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/*===========================================================================*/
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/** @brief I2C driver identifier.*/
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#if USE_AVR_I2C || defined(__DOXYGEN__)
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I2CDriver I2CD;
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#endif
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/*===========================================================================*/
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/* Driver local variables and types. */
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/*===========================================================================*/
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/*===========================================================================*/
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/* Driver local functions. */
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/*===========================================================================*/
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/**
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* @brief Wakes up the waiting thread.
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*
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* @param[in] i2cp pointer to the @p I2CDriver object
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* @param[in] msg wakeup message
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*
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* @notapi
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*/
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#define wakeup_isr(i2cp, msg) { \
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chSysLockFromIsr(); \
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if ((i2cp)->thread != NULL) { \
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Thread *tp = (i2cp)->thread; \
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(i2cp)->thread = NULL; \
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tp->p_u.rdymsg = (msg); \
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chSchReadyI(tp); \
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} \
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chSysUnlockFromIsr(); \
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}
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/*===========================================================================*/
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/* Driver interrupt handlers. */
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/*===========================================================================*/
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#if USE_AVR_I2C || defined(__DOXYGEN__)
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/**
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* @brief I2C event interrupt handler.
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*
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* @notapi
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*/
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CH_IRQ_HANDLER(TWI_vect) {
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CH_IRQ_PROLOGUE();
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I2CDriver *i2cp = &I2CD;
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switch (TWSR & 0xF8) {
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case TWI_START:
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case TWI_REPEAT_START:
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TWDR = (i2cp->addr << 1);
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if ((i2cp->txbuf == NULL) || (i2cp->txbytes == 0) || (i2cp->txidx == i2cp->txbytes)) {
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TWDR |= 0x01;
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}
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TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
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break;
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case TWI_MASTER_TX_ADDR_ACK:
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case TWI_MASTER_TX_DATA_ACK:
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if (i2cp->txidx < i2cp->txbytes) {
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TWDR = i2cp->txbuf[i2cp->txidx++];
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TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
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} else {
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if (i2cp->rxbuf && i2cp->rxbytes) {
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TWCR = ((1 << TWSTA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
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} else {
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TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
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wakeup_isr(i2cp, RDY_OK);
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}
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}
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break;
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case TWI_MASTER_RX_ADDR_ACK:
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if (i2cp->rxidx == (i2cp->rxbytes - 1)) {
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TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
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} else {
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TWCR = ((1 << TWEA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
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}
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break;
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case TWI_MASTER_RX_DATA_ACK:
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i2cp->rxbuf[i2cp->rxidx++] = TWDR;
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if (i2cp->rxidx == (i2cp->rxbytes - 1)) {
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TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
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} else {
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TWCR = ((1 << TWEA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
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}
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break;
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case TWI_MASTER_RX_DATA_NACK:
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i2cp->rxbuf[i2cp->rxidx] = TWDR;
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TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
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wakeup_isr(i2cp, RDY_OK);
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case TWI_MASTER_TX_ADDR_NACK:
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case TWI_MASTER_TX_DATA_NACK:
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case TWI_MASTER_RX_ADDR_NACK:
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i2cp->errors |= I2CD_ACK_FAILURE;
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break;
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case TWI_ARBITRATION_LOST:
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i2cp->errors |= I2CD_ARBITRATION_LOST;
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break;
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case TWI_BUS_ERROR:
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i2cp->errors |= I2CD_BUS_ERROR;
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break;
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default:
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/* FIXME: only gets here if there are other MASTERs in the bus */
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TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
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wakeup_isr(i2cp, RDY_RESET);
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}
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if (i2cp->errors != I2CD_NO_ERROR) {
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TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
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wakeup_isr(i2cp, RDY_RESET);
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}
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CH_IRQ_EPILOGUE();
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}
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#endif /* USE_AVR_I2C */
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/*===========================================================================*/
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/* Driver exported functions. */
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/*===========================================================================*/
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/**
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* @brief Low level I2C driver initialization.
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*
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* @notapi
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*/
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void i2c_lld_init(void) {
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i2cObjectInit(&I2CD);
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}
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/**
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* @brief Configures and activates the I2C peripheral.
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*
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* @param[in] i2cp pointer to the @p I2CDriver object
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*
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* @notapi
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*/
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void i2c_lld_start(I2CDriver *i2cp) {
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/* TODO: Test TWI without external pull-ups (use internal) */
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/* Configure prescaler to 1 */
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TWSR &= 0xF8;
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/* Configure baudrate */
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TWBR = ((F_CPU / i2cp->config->clock_speed) - 16) / 2;
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}
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/**
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* @brief Deactivates the I2C peripheral.
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*
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* @param[in] i2cp pointer to the @p I2CDriver object
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*
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* @notapi
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*/
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void i2c_lld_stop(I2CDriver *i2cp) {
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if (i2cp->state != I2C_STOP) {
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/* Disable TWI subsystem and stop all operations */
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TWCR &= ~(1 << TWEN);
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}
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}
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/**
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* @brief Receives data via the I2C bus as master.
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*
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* @param[in] i2cp pointer to the @p I2CDriver object
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* @param[in] addr slave device address
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* @param[out] rxbuf pointer to the receive buffer
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* @param[in] rxbytes number of bytes to be received
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* @param[in] timeout the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_INFINITE no timeout.
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* .
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* @return The operation status.
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* @retval RDY_OK if the function succeeded.
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* @retval RDY_RESET if one or more I2C errors occurred, the errors can
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* be retrieved using @p i2cGetErrors().
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* @retval RDY_TIMEOUT if a timeout occurred before operation end. <b>After a
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* timeout the driver must be stopped and restarted
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* because the bus is in an uncertain state</b>.
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*
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* @notapi
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*/
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msg_t i2c_lld_master_receive_timeout(I2CDriver *i2cp, i2caddr_t addr,
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uint8_t *rxbuf, size_t rxbytes,
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systime_t timeout) {
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i2cp->addr = addr;
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i2cp->txbuf = NULL;
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i2cp->txbytes = 0;
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i2cp->txidx = 0;
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i2cp->rxbuf = rxbuf;
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i2cp->rxbytes = rxbytes;
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i2cp->rxidx = 0;
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/* Send START */
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TWCR = ((1 << TWSTA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
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chSysLock();
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i2cp->thread = chThdSelf();
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chSchGoSleepS(THD_STATE_SUSPENDED);
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chSysUnlock();
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return chThdSelf()->p_u.rdymsg;
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}
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/**
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* @brief Transmits data via the I2C bus as master.
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*
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* @param[in] i2cp pointer to the @p I2CDriver object
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* @param[in] addr slave device address
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* @param[in] txbuf pointer to the transmit buffer
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* @param[in] txbytes number of bytes to be transmitted
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* @param[out] rxbuf pointer to the receive buffer
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* @param[in] rxbytes number of bytes to be received
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* @param[in] timeout the number of ticks before the operation timeouts,
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* the following special values are allowed:
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* - @a TIME_INFINITE no timeout.
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* .
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* @return The operation status.
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* @retval RDY_OK if the function succeeded.
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* @retval RDY_RESET if one or more I2C errors occurred, the errors can
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* be retrieved using @p i2cGetErrors().
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* @retval RDY_TIMEOUT if a timeout occurred before operation end. <b>After a
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* timeout the driver must be stopped and restarted
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* because the bus is in an uncertain state</b>.
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*
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* @notapi
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*/
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msg_t i2c_lld_master_transmit_timeout(I2CDriver *i2cp, i2caddr_t addr,
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const uint8_t *txbuf, size_t txbytes,
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uint8_t *rxbuf, size_t rxbytes,
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systime_t timeout) {
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i2cp->addr = addr;
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i2cp->txbuf = txbuf;
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i2cp->txbytes = txbytes;
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i2cp->txidx = 0;
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i2cp->rxbuf = rxbuf;
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i2cp->rxbytes = rxbytes;
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i2cp->rxidx = 0;
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TWCR = ((1 << TWSTA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
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chSysLock();
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i2cp->thread = chThdSelf();
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chSchGoSleepS(THD_STATE_SUSPENDED);
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chSysUnlock();
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return chThdSelf()->p_u.rdymsg;
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}
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#endif /* HAL_USE_I2C */
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/** @} */
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