I am attempting to send 13 bytes over UARTE1 on the nRF52840. I'm using the ASYNC API in Zephyr. When I look at the output on an oscilloscope, some of the bytes show up in the sent pattern. However, there are 2+ extra bytes that are sent along with the intended bytes; also, those extra bits are interspersed through the data I want. It's almost as if the data in the buffer are being corrupted during the transmission, but when I view those data in memory during debugging, they are the bytes I set.
I have set up the device with no parity bit and one stop bit. Could another setting account for the additional bits?
Here is the relevant code:
u8_t testBuffer[13] = {0xA5, 0x01, 0xF2, 0x00, 0x00, 0x0C, 0x00, 0x0C, 0x00, 0x61, 0x2F, 0x52, 0xEF};
void uartTXCallback(struct uart_event* evt, void* user_data){
switch(evt->type){
case UART_TX_DONE:
printk("UART_TX_DONE\n");
for(int i = 0; i<evt->data.tx.len;++i)
printk("%x:",evt->data.tx.buf[i]);
printk("\n");
break;
case UART_TX_ABORTED:
printk("UART_TX_ABORTED\n");
break;
case UART_RX_RDY:
printk("UART_RX_RDY\n");
break;
case UART_RX_BUF_REQUEST:
printk("UART_RX_BUF_REQUEST\n");
break;
case UART_RX_BUF_RELEASED:
printk("UART_RX_BUF_RELEASED\n");
break;
case UART_RX_DISABLED:
printk("UART_RX_DISABLED\n");
break;
case UART_RX_STOPPED:
printk("UART_RX_STOPPED\n");
break;
default:
printk("unknown event type!:%d\n", (int) evt->type);
}
}
int main(){
//set up UART1:
uart1dev = device_get_binding(DT_LABEL(DT_NODELABEL(uart1)));
int err;
err = uart_callback_set(uart1dev, uartTXCallback, NULL); //(uart_callback_t)
if(err != 0){
//printk("Error setting callback fn for UARTE1 tx:%d\n",err);
return;
}
size_t bufLen = sizeof(testBuffer);
while(1){
err=uart_tx(uart1dev, testBuffer, bufLen, 200);
if(err != 0){
printk("Something's up with the transmission: %d.\n", err);
}
k_busy_wait(200000);
}
}
