/**
* \internal
* Acts on slave address response. Checks for errors concerning master->slave
* handshake.
*
* \param[in,out] module Pointer to software module structure
*/
static void _i2c_master_async_address_response(
struct i2c_master_module *const module)
{
/* Sanity check arguments. */
Assert(module);
Assert(module->hw);
SercomI2cm *const i2c_module = &(module->hw->I2CM);
/* Check for error. Ignore bus-error; workaround for bus state stuck in
* BUSY.
*/
if (i2c_module->INTFLAG.reg & SERCOM_I2CM_INTFLAG_MB)
{
/* Clear write interrupt flag */
i2c_module->INTFLAG.reg = SERCOM_I2CM_INTENCLR_MB;
/* Check arbitration */
if (i2c_module->STATUS.reg & SERCOM_I2CM_STATUS_ARBLOST) {
/* Return busy */
module->status = STATUS_ERR_PACKET_COLLISION;
}
}
if (i2c_module->STATUS.reg & SERCOM_I2CM_STATUS_RXNACK) {
/* Return bad address value */
module->status = STATUS_ERR_BAD_ADDRESS;
module->buffer_remaining = 0;
if (module->send_stop) {
/* Send stop condition */
_i2c_master_wait_for_sync(module);
i2c_module->CTRLB.reg |= SERCOM_I2CM_CTRLB_CMD(3);
}
}
module->buffer_length = module->buffer_remaining;
/* Check for status OK. */
if (module->status == STATUS_BUSY) {
/* Call function based on transfer direction. */
if (module->transfer_direction == I2C_TRANSFER_WRITE) {
_i2c_master_write(module);
} else {
_i2c_master_read(module);
}
}
}
/**
* \brief Reads data packet from slave without sending a stop condition when done
*
* Reads a data packet from the specified slave address on the I<SUP>2</SUP>C
* bus without sending a stop condition when done, thus retaining ownership of
* the bus when done. To end the transaction, a
* \ref i2c_master_read_packet_wait "read" or
* \ref i2c_master_write_packet_wait "write" with stop condition must be
* performed.
*
* \note This will stall the device from any other operation. For
* interrupt-driven operation, see \ref i2c_master_read_packet_job.
*
* \param[in,out] module Pointer to software module struct
* \param[in,out] packet Pointer to I<SUP>2</SUP>C packet to transfer
*
* \return Status of reading packet.
* \retval STATUS_OK The packet was read successfully
* \retval STATUS_ERR_TIMEOUT If no response was given within
* specified timeout period
* \retval STATUS_ERR_DENIED If error on bus
* \retval STATUS_ERR_PACKET_COLLISION If arbitration is lost
* \retval STATUS_ERR_BAD_ADDRESS If slave is busy, or no slave
* acknowledged the address
*/
enum status_code i2c_master_read_packet_wait_no_stop(
struct i2c_master_module *const module,
struct i2c_packet *const packet)
{
/* Sanity check */
Assert(module);
Assert(module->hw);
Assert(packet);
#if I2C_MASTER_CALLBACK_MODE == true
/* Check if the I2C module is busy with a job. */
if (module->buffer_remaining > 0) {
return STATUS_BUSY;
}
#endif
module->send_stop = false;
return _i2c_master_read(module, packet);
}
/**
* \internal
* Interrupt handler for I<SUP>2</SUP>C master.
*
* \param[in] instance SERCOM instance that triggered the interrupt
*/
void _i2c_master_interrupt_handler(
uint8_t instance)
{
/* Get software module for callback handling */
struct i2c_master_module *module =
(struct i2c_master_module*)_sercom_instances[instance];
Assert(module);
SercomI2cm *const i2c_module = &(module->hw->I2CM);
/* Combine callback registered and enabled masks */
uint8_t callback_mask = module->enabled_callback &
module->registered_callback;
/* Check if the module should respond to address ack */
if ((module->buffer_length <= 0) && (module->buffer_remaining > 0)) {
/* Call function for address response */
_i2c_master_async_address_response(module);
/* Check if buffer write is done */
} else if ((module->buffer_length > 0) && (module->buffer_remaining <= 0) &&
(module->status == STATUS_BUSY) &&
(module->transfer_direction == I2C_TRANSFER_WRITE)) {
/* Stop packet operation */
i2c_module->INTENCLR.reg =
SERCOM_I2CM_INTENCLR_MB | SERCOM_I2CM_INTENCLR_SB;
module->buffer_length = 0;
module->status = STATUS_OK;
if (module->send_stop) {
/* Send stop condition */
_i2c_master_wait_for_sync(module);
i2c_module->CTRLB.reg |= SERCOM_I2CM_CTRLB_CMD(3);
} else {
/* Clear write interrupt flag */
i2c_module->INTFLAG.reg = SERCOM_I2CM_INTENCLR_MB;
}
if (callback_mask & (1 << I2C_MASTER_CALLBACK_WRITE_COMPLETE)) {
module->callbacks[I2C_MASTER_CALLBACK_WRITE_COMPLETE](module);
}
/* Continue buffer write/read */
} else if ((module->buffer_length > 0) && (module->buffer_remaining > 0)){
/* Check that bus ownership is not lost */
if (!(i2c_module->STATUS.reg & SERCOM_I2CM_STATUS_BUSSTATE(2))) {
module->status = STATUS_ERR_PACKET_COLLISION;
} else if (module->transfer_direction == I2C_TRANSFER_WRITE) {
_i2c_master_write(module);
} else {
_i2c_master_read(module);
}
}
/* Check if read buffer transfer is complete */
if ((module->buffer_length > 0) && (module->buffer_remaining <= 0) &&
(module->status == STATUS_BUSY) &&
(module->transfer_direction == I2C_TRANSFER_READ)) {
/* Stop packet operation */
i2c_module->INTENCLR.reg =
SERCOM_I2CM_INTENCLR_MB | SERCOM_I2CM_INTENCLR_SB;
module->buffer_length = 0;
module->status = STATUS_OK;
/* Call appropriate callback if enabled and registered */
if ((callback_mask & (1 << I2C_MASTER_CALLBACK_READ_COMPLETE))
&& (module->transfer_direction == I2C_TRANSFER_READ)) {
module->callbacks[I2C_MASTER_CALLBACK_READ_COMPLETE](module);
} else if ((callback_mask & (1 << I2C_MASTER_CALLBACK_WRITE_COMPLETE))
&& (module->transfer_direction == I2C_TRANSFER_WRITE)) {
module->callbacks[I2C_MASTER_CALLBACK_WRITE_COMPLETE](module);
}
}
/* Check for error */
if ((module->status != STATUS_BUSY) && (module->status != STATUS_OK)) {
/* Stop packet operation */
i2c_module->INTENCLR.reg = SERCOM_I2CM_INTENCLR_MB |
SERCOM_I2CM_INTENCLR_SB;
module->buffer_length = 0;
module->buffer_remaining = 0;
/* Send nack and stop command unless arbitration is lost */
if ((module->status != STATUS_ERR_PACKET_COLLISION) &&
module->send_stop) {
_i2c_master_wait_for_sync(module);
i2c_module->CTRLB.reg |= SERCOM_I2CM_CTRLB_ACKACT |
SERCOM_I2CM_CTRLB_CMD(3);
}
/* Call error callback if enabled and registered */
if (callback_mask & (1 << I2C_MASTER_CALLBACK_ERROR)) {
module->callbacks[I2C_MASTER_CALLBACK_ERROR](module);
}
}
}
