Hi, I made simple command shell via UART. It works fine when I type commands in terminal by hand. But I run into troubles when BLE chip is fed from MCU that send characters quickly. I can see several miliseconds delays between echoing characters and even some got lost and received command was corrupted. I hoped that received chars are stored in FIFO so there shouldn't be any data loss. Maybe I do it wrong in my code, any idea?
volatile int uart_cmd_ready; // complette command flag volatile int uart_cmd_index; // cmd buffer rec. char index char uart_cmd[UART_CMD_SIZE]; // cmd buffer that received chars are stored in
int uart_init(void) { // FIFO size must be 2^n app_uart_comm_params_t params; uint32_t err_code;
params.baud_rate=UART_BAUDR;
params.flow_control=APP_UART_FLOW_CONTROL_DISABLED; // HW flow disabled - we have only 2-wire UART connection
params.use_parity=false;
params.tx_pin_no=UART_TX_PIN;
params.rx_pin_no=UART_RX_PIN;
APP_UART_FIFO_INIT(¶ms, UART_RX_BUFFER_SIZE, UART_TX_BUFFER_SIZE, uart_evt_handler, APP_IRQ_PRIORITY_HIGH, err_code);
uart_cmd_ready=0;
uart_cmd_index=0;
memset(uart_cmd, 0, UART_CMD_SIZE);
return(err_code);
}
void uart_evt_handler(app_uart_evt_t *p_app_uart_event)
{
uint8_t c;
if (p_app_uart_event->evt_type==APP_UART_DATA_READY)
{
app_uart_get(&c); // read char from FIFO
app_uart_put(c); // and echo it immediately
if ((c==(uint8_t)'\r') || (c==(uint8_t)'\n') || (uart_cmd_index>=UART_CMD_SIZE-2)) // if end of line received CR or LF or buffer full
{
uart_cmd[uart_cmd_index++]='\0'; // zero string termination, inc. index
uart_cmd_ready=1; // set cmd complette flag
}
else if (c==8) // BackSpace
{
if (uart_cmd_index>0) // if index not at start position
uart_cmd_index--; // decrement index
}
else
uart_cmd[uart_cmd_index++]=c; // insert char to buffer in ic. index
}
}
after command is parsed I call
void clear_cmd(void) { sd_nvic_DisableIRQ(UART0_IRQn); // disable IRQ from UART uart_cmd[0]='\0'; // zero string in cmd buffer uart_cmd_ready=0; // reset cmd complette flag uart_cmd_index=0; // reset index sd_nvic_EnableIRQ(UART0_IRQn); // enable IRQ from UART }
