Hi,
We try to communicate between nRF51822 SoC and a GPS module through UART on a custom board but failed initializing UART.
More details:
- We use nRF51822 as a BLE peripheral using SoftDevice S110 v9.0
- BLE tasks work fine (initializing, communication with other devices...)
- On our design, we do not have flow control for UART communication
- In order to initialize UART communication we define the following functions:
Function 1 - event handler -> called in case of a UART event
void uart_event_handle(app_uart_evt_t * p_event) {
static uint8_t data_array[128];
static uint8_t index = 0;
uint32_t err_code;
switch (p_event->evt_type)
{
case APP_UART_DATA_READY:
UNUSED_VARIABLE(app_uart_get(&data_array[index]));
index++;
if ((data_array[index - 1] == '\n') || (index >= (8)))
{
if (err_code != NRF_ERROR_INVALID_STATE)
{
APP_ERROR_CHECK(err_code);
}
index = 0;
}
break;
case APP_UART_COMMUNICATION_ERROR:
APP_ERROR_HANDLER(p_event->data.error_communication);
break;
case APP_UART_FIFO_ERROR:
APP_ERROR_HANDLER(p_event->data.error_code);
break;
default:
break;
}
}
Function 2 - UART initializer
static void uart_init(void) {
uint32_t err_code;
const app_uart_comm_params_t comm_params =
{
UART_RXD_PIN,
UART_TXD_PIN,
UART_RXD_PIN,
UART_TXD_PIN,
APP_UART_FLOW_CONTROL_DISABLED,
false,
UART_BAUDRATE_BAUDRATE_Baud115200
};
APP_UART_FIFO_INIT( &comm_params,
UART_RX_BUF_SIZE,
UART_TX_BUF_SIZE,
uart_event_handle,
APP_IRQ_PRIORITY_LOW,
err_code);
APP_ERROR_CHECK(err_code);
}
Baud rate is the same between both devices. No control flow is possible. UART_RX_BUF_SIZE & UART_TX_BUF_SIZE are set equal to 64. We do not have RTS & CTS pin but we assume as control flow is disabled, their values in app_uart_comm_params_t are not really important.
Debugging, uart_init does not raise any error (according to APP_ERROR_CHECK). A few milliseconds after UART initialisation, uart_event_handle is triggered with APP_UART_COMMUNICATION_ERROR. data_error_communication has 0x0000000C value and the system stops.
Does anyone know about this problem? Are we doing something with UART initialization?
