/**
* \brief Initialize TWI master mode.
*
* \param p_twi Pointer to a TWI instance.
* \param p_opt Options for initializing the TWI module (see \ref twi_options_t).
*
* \return TWI_SUCCESS if initialization is complete, error code otherwise.
*/
uint32_t twi_master_init(Twi *p_twi, const twi_options_t *p_opt)
{
uint32_t status = TWI_SUCCESS;
/* Disable TWI interrupts */
p_twi->TWI_IDR = ~0UL;
/* Dummy read in status register */
p_twi->TWI_SR;
/* Reset TWI peripheral */
twi_reset(p_twi);
twi_enable_master_mode(p_twi);
/* Select the speed */
if (twi_set_speed(p_twi, p_opt->speed, p_opt->master_clk) == FAIL) {
/* The desired speed setting is rejected */
status = TWI_INVALID_ARGUMENT;
}
if (p_opt->smbus == 1) {
p_twi->TWI_CR = TWI_CR_QUICK;
}
return status;
}
/**
* \ingroup freertos_twi_peripheral_control_group
* \brief Initializes the FreeRTOS ASF TWI (I2C) master driver for the specified
* TWI port.
*
* freertos_twi_master_init() is an ASF specific FreeRTOS driver function. It
* must be called before any other ASF specific FreeRTOS driver functions
* attempt to access the same TWI port.
*
* If freertos_driver_parameters->operation_mode equals TWI_I2C_MASTER then
* freertos_twi_master_init() will configure the TWI port for master mode
* operation and enable the peripheral. If
* freertos_driver_parameters->operation_mode equals any other value then
* freertos_twi_master_init() will not take any action.
*
* Other ASF TWI functions can be called after freertos_twi_master_init() has
* completed successfully.
*
* The FreeRTOS ASF driver both installs and handles the TWI PDC interrupts.
* Users do not need to concern themselves with interrupt handling, and must
* not install their own interrupt handler.
*
* This driver is provided with an application note, and an example project that
* demonstrates the use of this function.
*
* \param p_twi The twi peripheral being initialized.
* \param freertos_driver_parameters Defines the driver behavior. See the
* freertos_peripheral_options_t documentation, and the application note that
* accompanies the ASF specific FreeRTOS functions.
*
* \return If the initialization completes successfully then a handle that can
* be used with FreeRTOS TWI read and write functions is returned. If
* the initialisation fails then NULL is returned.
*/
freertos_twi_if freertos_twi_master_init(Twi *p_twi,
const freertos_peripheral_options_t *const freertos_driver_parameters)
{
portBASE_TYPE twi_index;
bool is_valid_operating_mode;
freertos_twi_if return_value;
const enum peripheral_operation_mode valid_operating_modes[] = {TWI_I2C_MASTER};
/* Find the index into the all_twi_definitions array that holds details of
the p_twi peripheral. */
twi_index = get_pdc_peripheral_details(all_twi_definitions, MAX_TWIS,
(void *) p_twi);
/* Check the requested operating mode is valid for the peripheral. */
is_valid_operating_mode = check_requested_operating_mode(
freertos_driver_parameters->operation_mode,
valid_operating_modes,
sizeof(valid_operating_modes) /
sizeof(enum peripheral_operation_mode));
/* Don't do anything unless a valid p_twi pointer was used, and a valid
operating mode was requested. */
if ((twi_index < MAX_TWIS) && (is_valid_operating_mode == true)) {
/* This function must be called exactly once per supported twi. Check
it has not been called before. */
configASSERT(memcmp((void *)&(tx_dma_control[twi_index]),
&null_dma_control,
sizeof(null_dma_control)) == 0);
configASSERT(memcmp((void *)&(rx_dma_control[twi_index]),
&null_dma_control,
sizeof(null_dma_control)) == 0);
/* Enable the peripheral's clock. */
pmc_enable_periph_clk(
all_twi_definitions[twi_index].peripheral_id);
/* Ensure everything is disabled before configuration. */
pdc_disable_transfer(
all_twi_definitions[twi_index].pdc_base_address,
(PERIPH_PTCR_RXTDIS | PERIPH_PTCR_TXTDIS));
twi_disable_interrupt(
all_twi_definitions[twi_index].peripheral_base_address,
MASK_ALL_INTERRUPTS);
twi_reset(
all_twi_definitions[twi_index].peripheral_base_address);
switch (freertos_driver_parameters->operation_mode) {
case TWI_I2C_MASTER:
/* Call the standard ASF init function. */
twi_enable_master_mode(
all_twi_definitions[twi_index].peripheral_base_address);
break;
default:
/* No other modes are currently supported. */
break;
}
/* Create any required peripheral access mutexes and transaction complete
semaphores. This peripheral is half duplex so only a single access
mutex is required. */
create_peripheral_control_semaphores(
freertos_driver_parameters->options_flags,
&(tx_dma_control[twi_index]),
&(rx_dma_control[twi_index]));
/* Error interrupts are always enabled. */
twi_enable_interrupt(
all_twi_definitions[twi_index].peripheral_base_address,
IER_ERROR_INTERRUPTS);
/* Configure and enable the TWI interrupt in the interrupt controller. */
configure_interrupt_controller(
all_twi_definitions[twi_index].peripheral_irq,
freertos_driver_parameters->interrupt_priority);
return_value = (freertos_twi_if) p_twi;
} else {
return_value = NULL;
}
return return_value;
}