/** Interrupt driven FIFO fill function */
static int uarte_nrfx_fifo_fill(struct device *dev,
const u8_t *tx_data,
int len)
{
NRF_UARTE_Type *uarte = get_uarte_instance(dev);
struct uarte_nrfx_data *data = get_dev_data(dev);
const struct uarte_nrfx_config *config = get_dev_config(dev);
if (len > config->tx_buff_size) {
len = config->tx_buff_size;
}
nrf_uarte_event_clear(uarte, NRF_UARTE_EVENT_ENDTX);
/* Copy data to RAM buffer for EasyDMA transfer */
for (int i = 0; i < len; i++) {
data->tx_buffer[i] = tx_data[i];
}
nrf_uarte_tx_buffer_set(uarte, data->tx_buffer, len);
nrf_uarte_task_trigger(uarte, NRF_UARTE_TASK_STARTTX);
return len;
}
/**
* @brief Output a character in polled mode.
*
* @param dev UARTE device struct
* @param c Character to send
*
* @return Sent character
*/
static unsigned char uarte_nrfx_poll_out(struct device *dev,
unsigned char c)
{
NRF_UARTE_Type *uarte = get_uarte_instance(dev);
/* The UART API dictates that poll_out should wait for the transmitter
* to be empty before sending a character. However, the only way of
* telling if the transmitter became empty in the UARTE peripheral is
* to check if the ENDTX event for the previous transmission was set.
* Since this event is not cleared automatically when a new transmission
* is started, it must be cleared in software, and this leads to a rare
* yet possible race condition if the thread is preempted right after
* clearing the event but before sending a new character. The preempting
* thread, if it also called poll_out, would then wait for the ENDTX
* event that had no chance to become set.
* Because of this race condition, the while loop has to be placed
* after the write to TXD, and we can't wait for an empty transmitter
* before writing. This is a trade-off between losing a byte once in a
* blue moon against hanging up the whole thread permanently
*/
/* reset transmitter ready state */
nrf_uarte_event_clear(uarte, NRF_UARTE_EVENT_ENDTX);
/* send a character */
nrf_uarte_tx_buffer_set(uarte, &c, 1);
nrf_uarte_task_trigger(uarte, NRF_UARTE_TASK_STARTTX);
/* Wait for transmitter to be ready */
while (!nrf_uarte_event_check(uarte, NRF_UARTE_EVENT_ENDTX)) {
}
/* If there is nothing to send, driver will save an energy
* when TX is stopped.
*/
nrf_uarte_task_trigger(uarte, NRF_UARTE_TASK_STOPTX);
return c;
}
static int uarte_instance_init(struct device *dev,
const struct uarte_init_config *config,
u8_t interrupts_active)
{
int err;
NRF_UARTE_Type *uarte = get_uarte_instance(dev);
struct uarte_nrfx_data *data = get_dev_data(dev);
nrf_gpio_pin_write(config->pseltxd, 1);
nrf_gpio_cfg_output(config->pseltxd);
nrf_gpio_cfg_input(config->pselrxd, NRF_GPIO_PIN_NOPULL);
nrf_uarte_txrx_pins_set(uarte,
config->pseltxd,
config->pselrxd);
if (config->hwfc == NRF_UARTE_HWFC_ENABLED) {
nrf_gpio_pin_write(config->pselrts, 1);
nrf_gpio_cfg_output(config->pselrts);
nrf_gpio_cfg_input(config->pselcts, NRF_GPIO_PIN_NOPULL);
nrf_uarte_hwfc_pins_set(uarte,
config->pselrts,
config->pselcts);
}
/* Configure flow control and parity checking */
nrf_uarte_configure(uarte,
config->parity,
config->hwfc);
err = baudrate_set(dev, config->baudrate);
if (err) {
return err;
}
/* Enable receiver and transmitter */
nrf_uarte_enable(uarte);
nrf_uarte_event_clear(uarte, NRF_UARTE_EVENT_ENDRX);
nrf_uarte_rx_buffer_set(uarte, &data->rx_data, 1);
nrf_uarte_task_trigger(uarte, NRF_UARTE_TASK_STARTRX);
#if UARTE_INTERRUPT_DRIVEN
if (interrupts_active) {
/* Set ENDTX event by requesting fake (zero-length) transfer.
* Pointer to RAM variable (data->tx_buffer) is set because
* otherwise such operation may result in HardFault or RAM
* corruption.
*/
nrf_uarte_tx_buffer_set(uarte, data->tx_buffer, 0);
nrf_uarte_task_trigger(uarte, NRF_UARTE_TASK_STARTTX);
/* switch off transmitter to save an energy */
nrf_uarte_task_trigger(uarte, NRF_UARTE_TASK_STOPTX);
}
#endif /* UARTE_INTERRUPT_DRIVEN */
return 0;
}
nrfx_err_t nrfx_uarte_tx(nrfx_uarte_t const * p_instance,
uint8_t const * p_data,
size_t length)
{
uarte_control_block_t * p_cb = &m_cb[p_instance->drv_inst_idx];
NRFX_ASSERT(p_cb->state == NRFX_DRV_STATE_INITIALIZED);
NRFX_ASSERT(p_data);
NRFX_ASSERT(length > 0);
NRFX_ASSERT(UARTE_LENGTH_VALIDATE(p_instance->drv_inst_idx, length));
nrfx_err_t err_code;
// EasyDMA requires that transfer buffers are placed in DataRAM,
// signal error if the are not.
if (!nrfx_is_in_ram(p_data))
{
err_code = NRFX_ERROR_INVALID_ADDR;
NRFX_LOG_WARNING("Function: %s, error code: %s.",
__func__,
NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
if (nrfx_uarte_tx_in_progress(p_instance))
{
err_code = NRFX_ERROR_BUSY;
NRFX_LOG_WARNING("Function: %s, error code: %s.",
__func__,
NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}
p_cb->tx_buffer_length = length;
p_cb->p_tx_buffer = p_data;
NRFX_LOG_INFO("Transfer tx_len: %d.", p_cb->tx_buffer_length);
NRFX_LOG_DEBUG("Tx data:");
NRFX_LOG_HEXDUMP_DEBUG(p_cb->p_tx_buffer,
p_cb->tx_buffer_length * sizeof(p_cb->p_tx_buffer[0]));
err_code = NRFX_SUCCESS;
nrf_uarte_event_clear(p_instance->p_reg, NRF_UARTE_EVENT_ENDTX);
nrf_uarte_event_clear(p_instance->p_reg, NRF_UARTE_EVENT_TXSTOPPED);
nrf_uarte_tx_buffer_set(p_instance->p_reg, p_cb->p_tx_buffer, p_cb->tx_buffer_length);
nrf_uarte_task_trigger(p_instance->p_reg, NRF_UARTE_TASK_STARTTX);
if (p_cb->handler == NULL)
{
bool endtx;
bool txstopped;
do
{
endtx = nrf_uarte_event_check(p_instance->p_reg, NRF_UARTE_EVENT_ENDTX);
txstopped = nrf_uarte_event_check(p_instance->p_reg, NRF_UARTE_EVENT_TXSTOPPED);
}
while ((!endtx) && (!txstopped));
if (txstopped)
{
err_code = NRFX_ERROR_FORBIDDEN;
}
p_cb->tx_buffer_length = 0;
}
NRFX_LOG_INFO("Function: %s, error code: %s.", __func__, NRFX_LOG_ERROR_STRING_GET(err_code));
return err_code;
}