/**@brief GPIOTE event handler.
*
* @param[in] event_pins_low_to_high Mask telling which pin(s) generated an event from low->high.
* @param[in] event_pins_high_to_low Mask telling which pin(s) generated an event from high->low.
*/
static void gpiote_uart_event_handler(uint32_t event_pins_low_to_high,
uint32_t event_pins_high_to_low)
{
if ((event_pins_high_to_low & event_pins_low_to_high & m_pin_cts_mask) != 0)
{
// We have an indication from GPIOTE that the CTS pin has toggled high->low and low->high.
// If this occurs, we must read the active pins in the GPIOTE module ourself.
uint32_t active_pins;
uint32_t err_code;
err_code = app_gpiote_pins_state_get(m_gpiote_uid, &active_pins);
if (err_code != NRF_SUCCESS)
{
// Pin reading was not possible, even though an event from GPIOTE was received that the
// CTS pin toggled. If pin double toggled but status cannot be fetched we silently
// return and keep the current UART status as-is.
return;
}
event_pins_low_to_high &= active_pins;
event_pins_high_to_low &= ~active_pins;
}
if ((event_pins_high_to_low & m_pin_cts_mask) != 0)
{
on_uart_event(ON_CTS_LOW);
}
else if ((event_pins_low_to_high & m_pin_cts_mask) != 0)
{
on_uart_event(ON_CTS_HIGH);
}
else
{
// Do nothing, as the CTS pin didn't toggle.
}
}
/**@brief Function for the GPIOTE event handler.
*/
static void gpiote_uart_event_handler(nrf_drv_gpiote_pin_t pin, nrf_gpiote_polarity_t action)
{
if (nrf_drv_gpiote_in_is_set(pin))
{
on_uart_event(ON_CTS_HIGH);
}
else
{
on_uart_event(ON_CTS_LOW);
}
}
uint32_t app_uart_close(uint16_t app_uart_uid)
{
if (app_uart_uid < UART_INSTANCE_GPIOTE_BASE)
{
on_uart_event(ON_UART_CLOSE);
return NRF_SUCCESS;
}
on_uart_event(ON_UART_CLOSE);
nrf_drv_gpiote_in_uninit(NRF_UART0->PSELCTS);
return NRF_SUCCESS;
}
/**@brief Function for the UART Interrupt handler.
*
* @details UART interrupt handler to process TX Ready when TXD is available, RX Ready when a byte
* is received, or in case of error when receiving a byte.
*/
void UART0_IRQHandler(void)
{
// Handle reception
if (NRF_UART0->EVENTS_RXDRDY != 0)
{
uint32_t err_code;
// Clear UART RX event flag
NRF_UART0->EVENTS_RXDRDY = 0;
// Write received byte to FIFO
err_code = app_fifo_put(&m_rx_fifo, (uint8_t)NRF_UART0->RXD);
if (err_code != NRF_SUCCESS)
{
app_uart_evt_t app_uart_event;
app_uart_event.evt_type = APP_UART_FIFO_ERROR;
app_uart_event.data.error_code = err_code;
m_event_handler(&app_uart_event);
}
// Notify that new data is available if this was first byte put in the buffer.
else if (FIFO_LENGTH(m_rx_fifo) == 1)
{
app_uart_evt_t app_uart_event;
app_uart_event.evt_type = APP_UART_DATA_READY;
m_event_handler(&app_uart_event);
}
else
{
// Do nothing, only send event if first byte was added or overflow in FIFO occurred.
}
}
// Handle transmission.
if (NRF_UART0->EVENTS_TXDRDY != 0)
{
// Clear UART TX event flag.
NRF_UART0->EVENTS_TXDRDY = 0;
on_uart_event(ON_TX_READY);
}
// Handle errors.
if (NRF_UART0->EVENTS_ERROR != 0)
{
uint32_t error_source;
app_uart_evt_t app_uart_event;
// Clear UART ERROR event flag.
NRF_UART0->EVENTS_ERROR = 0;
// Clear error source.
error_source = NRF_UART0->ERRORSRC;
NRF_UART0->ERRORSRC = error_source;
app_uart_event.evt_type = APP_UART_COMMUNICATION_ERROR;
app_uart_event.data.error_communication = error_source;
m_event_handler(&app_uart_event);
}
}
uint32_t app_uart_put(uint8_t byte)
{
uint32_t err_code;
err_code = app_fifo_put(&m_tx_fifo, byte);
on_uart_event(ON_UART_PUT);
return err_code;
}
uint32_t app_uart_put(uint8_t byte)
{
uint32_t err_code = NRF_SUCCESS;
if (m_current_state != UART_READY)
{
err_code = NRF_ERROR_NO_MEM;
}
else
{
m_tx_byte = byte;
on_uart_event(ON_UART_PUT);
}
return err_code;
}
/**@brief Function for handling the UART Interrupt.
*
* @details UART interrupt handler to process TX Ready when TXD is available, RX Ready when a byte
* is received, or in case of error when receiving a byte.
*/
void UART_IRQHandler(void)
{
// Handle reception
if ((NRF_UART0->EVENTS_RXDRDY != 0) && (NRF_UART0->INTENSET & UART_INTENSET_RXDRDY_Msk))
{
app_uart_evt_t app_uart_event;
// Clear UART RX event flag
NRF_UART0->EVENTS_RXDRDY = 0;
m_rx_byte = (uint8_t)NRF_UART0->RXD;
app_uart_event.evt_type = APP_UART_DATA;
app_uart_event.data.value = m_rx_byte;
m_event_handler(&app_uart_event);
}
// Handle transmission.
if ((NRF_UART0->EVENTS_TXDRDY != 0) && (NRF_UART0->INTENSET & UART_INTENSET_TXDRDY_Msk))
{
// Clear UART TX event flag.
NRF_UART0->EVENTS_TXDRDY = 0;
on_uart_event(ON_TX_READY);
}
// Handle errors.
if ((NRF_UART0->EVENTS_ERROR != 0) && (NRF_UART0->INTENSET & UART_INTENSET_ERROR_Msk))
{
uint32_t error_source;
app_uart_evt_t app_uart_event;
// Clear UART ERROR event flag.
NRF_UART0->EVENTS_ERROR = 0;
// Clear error source.
error_source = NRF_UART0->ERRORSRC;
NRF_UART0->ERRORSRC = error_source;
app_uart_event.evt_type = APP_UART_COMMUNICATION_ERROR;
app_uart_event.data.error_communication = error_source;
m_event_handler(&app_uart_event);
}
}
uint32_t app_uart_init(const app_uart_comm_params_t * p_comm_params,
app_uart_buffers_t * p_buffers,
app_uart_event_handler_t event_handler,
app_irq_priority_t irq_priority,
uint16_t * p_app_uart_uid)
{
uint32_t err_code;
m_current_state = UART_OFF;
m_event_handler = event_handler;
m_rx_byte = BYTE_INVALID;
// Configure RX and TX pins.
nrf_gpio_pin_set(p_comm_params->tx_pin_no);
nrf_gpio_cfg_output(p_comm_params->tx_pin_no);
nrf_gpio_cfg_input(p_comm_params->rx_pin_no, NRF_GPIO_PIN_PULLUP);
NRF_UART0->PSELTXD = p_comm_params->tx_pin_no;
NRF_UART0->PSELRXD = p_comm_params->rx_pin_no;
// Configure baud rate and parity.
NRF_UART0->BAUDRATE = (p_comm_params->baud_rate << UART_BAUDRATE_BAUDRATE_Pos);
if (p_comm_params->use_parity)
{
NRF_UART0->CONFIG = (UART_CONFIG_PARITY_Included << UART_CONFIG_PARITY_Pos);
}
else
{
NRF_UART0->CONFIG = (UART_CONFIG_PARITY_Excluded << UART_CONFIG_PARITY_Pos);
}
if (p_comm_params->flow_control == APP_UART_FLOW_CONTROL_LOW_POWER)
{
if (!nrf_drv_gpiote_is_init())
{
err_code = nrf_drv_gpiote_init();
if (err_code != NRF_SUCCESS)
{
return err_code;
}
}
// Configure hardware flow control.
nrf_drv_gpiote_out_config_t rts_config = GPIOTE_CONFIG_OUT_SIMPLE(true);
err_code = nrf_drv_gpiote_out_init(p_comm_params->rts_pin_no, &rts_config);
if (err_code != NRF_SUCCESS)
{
return err_code;
}
NRF_UART0->PSELCTS = UART_PIN_DISCONNECTED;
NRF_UART0->PSELRTS = p_comm_params->rts_pin_no;
NRF_UART0->CONFIG |= (UART_CONFIG_HWFC_Enabled << UART_CONFIG_HWFC_Pos);
// Setup the gpiote to handle pin events on cts-pin.
// For the UART we want to detect both low->high and high->low transitions in order to
// know when to activate/de-activate the TX/RX in the UART.
// Configure pin.
nrf_drv_gpiote_in_config_t cts_config = GPIOTE_CONFIG_IN_SENSE_TOGGLE(false);
err_code = nrf_drv_gpiote_in_init(p_comm_params->cts_pin_no, &cts_config, gpiote_uart_event_handler);
if (err_code != NRF_SUCCESS)
{
return err_code;
}
nrf_drv_gpiote_in_event_enable(p_comm_params->cts_pin_no, true);
// UART CTS pin is active when low.
if (nrf_drv_gpiote_in_is_set(p_comm_params->cts_pin_no))
{
on_uart_event(ON_CTS_HIGH);
}
else
{
on_uart_event(ON_CTS_LOW);
}
}
else if (p_comm_params->flow_control == APP_UART_FLOW_CONTROL_ENABLED)
{
uart_standard_flow_control_init(p_comm_params);
m_current_state = UART_READY;
}
else
{
uart_no_flow_control_init();
m_current_state = UART_READY;
}
if (*p_app_uart_uid == UART_INSTANCE_ID_INVALID)
{
*p_app_uart_uid = m_instance_counter++;
}
// Enable UART interrupt
NRF_UART0->INTENCLR = 0xffffffffUL;
NRF_UART0->INTENSET = (UART_INTENSET_RXDRDY_Set << UART_INTENSET_RXDRDY_Pos) |
(UART_INTENSET_TXDRDY_Set << UART_INTENSET_TXDRDY_Pos) |
(UART_INTENSET_ERROR_Set << UART_INTENSET_ERROR_Pos);
NVIC_ClearPendingIRQ(UART_IRQ);
NVIC_SetPriority(UART_IRQ, irq_priority);
NVIC_EnableIRQ(UART_IRQ);
return NRF_SUCCESS;
}
uint32_t app_uart_init(const app_uart_comm_params_t * p_comm_params,
app_uart_buffers_t * p_buffers,
app_uart_event_handler_t event_handler,
app_irq_priority_t irq_priority)
{
uint32_t err_code;
uint32_t gpiote_high_pins;
uint32_t gpiote_pin_low_high_mask = 0;
uint32_t gpiote_pin_high_low_mask = 0;
m_current_state = UART_OFF;
m_event_handler = event_handler;
// Configure buffer RX buffer.
err_code = app_fifo_init(&m_rx_fifo, p_buffers->rx_buf, p_buffers->rx_buf_size);
if (err_code != NRF_SUCCESS)
{
// Propagate error code.
return err_code;
}
// Configure buffer TX buffer.
err_code = app_fifo_init(&m_tx_fifo, p_buffers->tx_buf, p_buffers->tx_buf_size);
if (err_code != NRF_SUCCESS)
{
// Propagate error code.
return err_code;
}
// Configure RX and TX pins.
nrf_gpio_cfg_output(p_comm_params->tx_pin_no);
nrf_gpio_cfg_input(p_comm_params->rx_pin_no, NRF_GPIO_PIN_NOPULL);
NRF_UART0->PSELTXD = p_comm_params->tx_pin_no;
NRF_UART0->PSELRXD = p_comm_params->rx_pin_no;
// Configure baud rate and parity.
NRF_UART0->BAUDRATE = (p_comm_params->baud_rate << UART_BAUDRATE_BAUDRATE_Pos);
if (p_comm_params->use_parity)
{
NRF_UART0->CONFIG = (UART_CONFIG_PARITY_Included << UART_CONFIG_PARITY_Pos);
}
else
{
NRF_UART0->CONFIG = (UART_CONFIG_PARITY_Excluded << UART_CONFIG_PARITY_Pos);
}
if (p_comm_params->use_hardware_flow_control)
{
// Configure hardware flow control.
nrf_gpio_cfg_output(p_comm_params->rts_pin_no);
NRF_GPIO->OUT = 1 << p_comm_params->rts_pin_no;
NRF_UART0->PSELCTS = UART_PIN_DISCONNECTED;
NRF_UART0->PSELRTS = p_comm_params->rts_pin_no;
NRF_UART0->CONFIG |= (UART_CONFIG_HWFC_Enabled << UART_CONFIG_HWFC_Pos);
// Setup the gpiote to handle pin events on cts-pin.
// For the UART we want to detect both low->high and high->low transistions in order to
// know when to activate/deactivate the TX/RX in the UART.
// Configure pin.
m_pin_cts_mask = (1 << p_comm_params->cts_pin_no);
GPIO_PIN_CONFIG(p_comm_params->cts_pin_no,
GPIO_PIN_CNF_DIR_Input,
GPIO_PIN_CNF_INPUT_Connect,
GPIO_PIN_CNF_PULL_Disabled,
GPIO_PIN_CNF_DRIVE_S0S1,
GPIO_PIN_CNF_SENSE_Low);
gpiote_pin_low_high_mask = (1 << p_comm_params->cts_pin_no);
gpiote_pin_high_low_mask = (1 << p_comm_params->cts_pin_no);
err_code = app_gpiote_user_register(&m_gpiote_uid,
gpiote_pin_low_high_mask,
gpiote_pin_high_low_mask,
gpiote_uart_event_handler);
if (err_code != NRF_SUCCESS)
{
return err_code;
}
err_code = app_gpiote_pins_state_get(m_gpiote_uid, &gpiote_high_pins);
if (err_code != NRF_SUCCESS)
{
return err_code;
}
err_code = app_gpiote_user_enable(m_gpiote_uid);
if (err_code != NRF_SUCCESS)
{
return err_code;
}
// UART CTS pin is active when low.
if ((gpiote_high_pins & (1 << p_comm_params->cts_pin_no)) == 0)
{
on_uart_event(ON_CTS_LOW);
}
else
{
on_uart_event(ON_CTS_HIGH);
}
}
else
{
uart_no_flow_control_init();
m_current_state = UART_READY;
}
// Enable UART interrupt
NRF_UART0->INTENCLR = 0xffffffffUL;
NRF_UART0->INTENSET = (UART_INTENSET_RXDRDY_Set << UART_INTENSET_RXDRDY_Pos) |
(UART_INTENSET_TXDRDY_Set << UART_INTENSET_TXDRDY_Pos) |
(UART_INTENSET_ERROR_Set << UART_INTENSET_ERROR_Pos);
NVIC_ClearPendingIRQ(UART0_IRQn);
NVIC_SetPriority(UART0_IRQn, irq_priority);
NVIC_EnableIRQ(UART0_IRQn);
return NRF_SUCCESS;
}
uint32_t app_uart_close(uint16_t app_uart_uid)
{
on_uart_event(ON_UART_CLOSE);
return 0;
}