diff options
Diffstat (limited to 'os/hal/platforms/AVR/i2c_lld.c')
| -rw-r--r-- | os/hal/platforms/AVR/i2c_lld.c | 293 |
1 files changed, 293 insertions, 0 deletions
diff --git a/os/hal/platforms/AVR/i2c_lld.c b/os/hal/platforms/AVR/i2c_lld.c new file mode 100644 index 000000000..4795031ba --- /dev/null +++ b/os/hal/platforms/AVR/i2c_lld.c @@ -0,0 +1,293 @@ +/*
+ ChibiOS/RT - Copyright (C) 2006,2007,2008,2009,2010,
+ 2011,2012 Giovanni Di Sirio.
+
+ This file is part of ChibiOS/RT.
+
+ ChibiOS/RT is free software; you can redistribute it and/or modify
+ it under the terms of the GNU General Public License as published by
+ the Free Software Foundation; either version 3 of the License, or
+ (at your option) any later version.
+
+ ChibiOS/RT is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ GNU General Public License for more details.
+
+ You should have received a copy of the GNU General Public License
+ along with this program. If not, see <http://www.gnu.org/licenses/>.
+*/
+
+/**
+ * @file AVR/i2c_lld.c
+ * @brief AVR I2C subsystem low level driver source.
+ *
+ * @addtogroup I2C
+ * @{
+ */
+
+#include "ch.h"
+#include "hal.h"
+
+#if HAL_USE_I2C || defined(__DOXYGEN__)
+
+/*===========================================================================*/
+/* Driver local definitions. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver exported variables. */
+/*===========================================================================*/
+
+/** @brief I2C driver identifier.*/
+#if USE_AVR_I2C || defined(__DOXYGEN__)
+I2CDriver I2CD;
+#endif
+
+/*===========================================================================*/
+/* Driver local variables. */
+/*===========================================================================*/
+
+/*===========================================================================*/
+/* Driver local functions. */
+/*===========================================================================*/
+
+/**
+ * @brief Wakes up the waiting thread.
+ *
+ * @param[in] i2cp pointer to the @p I2CDriver object
+ * @param[in] msg wakeup message
+ *
+ * @notapi
+ */
+#define wakeup_isr(i2cp, msg) { \
+ chSysLockFromIsr(); \
+ if ((i2cp)->thread != NULL) { \
+ Thread *tp = (i2cp)->thread; \
+ (i2cp)->thread = NULL; \
+ tp->p_u.rdymsg = (msg); \
+ chSchReadyI(tp); \
+ } \
+ chSysUnlockFromIsr(); \
+}
+
+/*===========================================================================*/
+/* Driver interrupt handlers. */
+/*===========================================================================*/
+
+#if USE_AVR_I2C || defined(__DOXYGEN__)
+/**
+ * @brief I2C event interrupt handler.
+ *
+ * @notapi
+ */
+CH_IRQ_HANDLER(TWI_vect) {
+ CH_IRQ_PROLOGUE();
+
+ I2CDriver *i2cp = &I2CD;
+
+ switch (TWSR & 0xF8) {
+ case TWI_START:
+ case TWI_REPEAT_START:
+ TWDR = (i2cp->addr << 1);
+ if ((i2cp->txbuf == NULL) || (i2cp->txbytes == 0) || (i2cp->txidx == i2cp->txbytes)) {
+ TWDR |= 0x01;
+ }
+ TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
+ break;
+ case TWI_MASTER_TX_ADDR_ACK:
+ case TWI_MASTER_TX_DATA_ACK:
+ if (i2cp->txidx < i2cp->txbytes) {
+ TWDR = i2cp->txbuf[i2cp->txidx++];
+ TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
+ } else {
+ if (i2cp->rxbuf && i2cp->rxbytes) {
+ TWCR = ((1 << TWSTA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
+ } else {
+ TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
+ wakeup_isr(i2cp, RDY_OK);
+ }
+ }
+ break;
+ case TWI_MASTER_RX_ADDR_ACK:
+ if (i2cp->rxidx == (i2cp->rxbytes - 1)) {
+ TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
+ } else {
+ TWCR = ((1 << TWEA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
+ }
+ break;
+ case TWI_MASTER_RX_DATA_ACK:
+ i2cp->rxbuf[i2cp->rxidx++] = TWDR;
+ if (i2cp->rxidx == (i2cp->rxbytes - 1)) {
+ TWCR = ((1 << TWINT) | (1 << TWEN) | (1 << TWIE));
+ } else {
+ TWCR = ((1 << TWEA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
+ }
+ break;
+ case TWI_MASTER_RX_DATA_NACK:
+ i2cp->rxbuf[i2cp->rxidx] = TWDR;
+ TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
+ wakeup_isr(i2cp, RDY_OK);
+ case TWI_MASTER_TX_ADDR_NACK:
+ case TWI_MASTER_TX_DATA_NACK:
+ case TWI_MASTER_RX_ADDR_NACK:
+ i2cp->errors |= I2CD_ACK_FAILURE;
+ break;
+ case TWI_ARBITRATION_LOST:
+ i2cp->errors |= I2CD_ARBITRATION_LOST;
+ break;
+ case TWI_BUS_ERROR:
+ i2cp->errors |= I2CD_BUS_ERROR;
+ break;
+ default:
+ /* FIXME: only gets here if there are other MASTERs in the bus */
+ TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
+ wakeup_isr(i2cp, RDY_RESET);
+ }
+
+ if (i2cp->errors != I2CD_NO_ERROR) {
+ TWCR = ((1 << TWSTO) | (1 << TWINT) | (1 << TWEN));
+ wakeup_isr(i2cp, RDY_RESET);
+ }
+
+ CH_IRQ_EPILOGUE();
+}
+#endif /* USE_AVR_I2C */
+
+/*===========================================================================*/
+/* Driver exported functions. */
+/*===========================================================================*/
+
+/**
+ * @brief Low level I2C driver initialization.
+ *
+ * @notapi
+ */
+void i2c_lld_init(void) {
+ i2cObjectInit(&I2CD);
+}
+
+/**
+ * @brief Configures and activates the I2C peripheral.
+ *
+ * @param[in] i2cp pointer to the @p I2CDriver object
+ *
+ * @notapi
+ */
+void i2c_lld_start(I2CDriver *i2cp) {
+
+ /* TODO: Test TWI without external pull-ups (use internal) */
+
+ /* Configure prescaler to 1 */
+ TWSR &= 0xF8;
+
+ /* Configure baudrate */
+ TWBR = ((F_CPU / i2cp->config->clock_speed) - 16) / 2;
+}
+
+/**
+ * @brief Deactivates the I2C peripheral.
+ *
+ * @param[in] i2cp pointer to the @p I2CDriver object
+ *
+ * @notapi
+ */
+void i2c_lld_stop(I2CDriver *i2cp) {
+
+ if (i2cp->state != I2C_STOP) {
+ /* Disable TWI subsystem and stop all operations */
+ TWCR &= ~(1 << TWEN);
+ }
+}
+
+/**
+ * @brief Receives data via the I2C bus as master.
+ *
+ * @param[in] i2cp pointer to the @p I2CDriver object
+ * @param[in] addr slave device address
+ * @param[out] rxbuf pointer to the receive buffer
+ * @param[in] rxbytes number of bytes to be received
+ * @param[in] timeout the number of ticks before the operation timeouts,
+ * the following special values are allowed:
+ * - @a TIME_INFINITE no timeout.
+ * .
+ * @return The operation status.
+ * @retval RDY_OK if the function succeeded.
+ * @retval RDY_RESET if one or more I2C errors occurred, the errors can
+ * be retrieved using @p i2cGetErrors().
+ * @retval RDY_TIMEOUT if a timeout occurred before operation end. <b>After a
+ * timeout the driver must be stopped and restarted
+ * because the bus is in an uncertain state</b>.
+ *
+ * @notapi
+ */
+msg_t i2c_lld_master_receive_timeout(I2CDriver *i2cp, i2caddr_t addr,
+ uint8_t *rxbuf, size_t rxbytes,
+ systime_t timeout) {
+ i2cp->addr = addr;
+ i2cp->txbuf = NULL;
+ i2cp->txbytes = 0;
+ i2cp->txidx = 0;
+ i2cp->rxbuf = rxbuf;
+ i2cp->rxbytes = rxbytes;
+ i2cp->rxidx = 0;
+
+ /* Send START */
+ TWCR = ((1 << TWSTA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
+
+ chSysLock();
+ i2cp->thread = chThdSelf();
+ chSchGoSleepS(THD_STATE_SUSPENDED);
+ chSysUnlock();
+
+ return chThdSelf()->p_u.rdymsg;
+}
+
+/**
+ * @brief Transmits data via the I2C bus as master.
+ *
+ * @param[in] i2cp pointer to the @p I2CDriver object
+ * @param[in] addr slave device address
+ * @param[in] txbuf pointer to the transmit buffer
+ * @param[in] txbytes number of bytes to be transmitted
+ * @param[out] rxbuf pointer to the receive buffer
+ * @param[in] rxbytes number of bytes to be received
+ * @param[in] timeout the number of ticks before the operation timeouts,
+ * the following special values are allowed:
+ * - @a TIME_INFINITE no timeout.
+ * .
+ * @return The operation status.
+ * @retval RDY_OK if the function succeeded.
+ * @retval RDY_RESET if one or more I2C errors occurred, the errors can
+ * be retrieved using @p i2cGetErrors().
+ * @retval RDY_TIMEOUT if a timeout occurred before operation end. <b>After a
+ * timeout the driver must be stopped and restarted
+ * because the bus is in an uncertain state</b>.
+ *
+ * @notapi
+ */
+msg_t i2c_lld_master_transmit_timeout(I2CDriver *i2cp, i2caddr_t addr,
+ const uint8_t *txbuf, size_t txbytes,
+ uint8_t *rxbuf, size_t rxbytes,
+ systime_t timeout) {
+ i2cp->addr = addr;
+ i2cp->txbuf = txbuf;
+ i2cp->txbytes = txbytes;
+ i2cp->txidx = 0;
+ i2cp->rxbuf = rxbuf;
+ i2cp->rxbytes = rxbytes;
+ i2cp->rxidx = 0;
+
+ TWCR = ((1 << TWSTA) | (1 << TWINT) | (1 << TWEN) | (1 << TWIE));
+
+ chSysLock();
+ i2cp->thread = chThdSelf();
+ chSchGoSleepS(THD_STATE_SUSPENDED);
+ chSysUnlock();
+
+ return chThdSelf()->p_u.rdymsg;
+}
+
+#endif /* HAL_USE_I2C */
+
+/** @} */
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