RE: Delay in 1st byte of sent UART message

Cindy Xiao — Fri, 04 Mar 2016 03:26:27 GMT

Thanks for the reply, Martin. The device I'm using is also serving as a BLE client; the gps_init function took place just before I initialized the BLE stack, called device_manager_init, db_discovery_init, and scan_start. I think one of these had something to do with the byte being delayed.

Here is my original code:

int main(void)
{
bool erase_bonds;

// Initialize.
APP_TIMER_INIT(APP_TIMER_PRESCALER, APP_TIMER_MAX_TIMERS, APP_TIMER_OP_QUEUE_SIZE, NULL);

uart_init();
gps_init();
buttons_leds_init(&erase_bonds);

ble_stack_init();
device_manager_init(erase_bonds);
db_discovery_init();
bas_c_init();

scan_start();
for (;; )
{
    power_manage();
}
}

Moving the uart_init and gps_init to after all of the bluetooth initialization functions, as well as scan_start, seemed to resolve my issue.

RE: Delay in 1st byte of sent UART message

MartinBL — Thu, 03 Mar 2016 11:22:18 GMT

I have tried this exact code and it seems to work fine on my system. I don't use any flow control and I call uart_init() gps_init(); in main. That's it. Are you doing anything else in your application? Could it be your software flow control?

Logic trace: