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MQX with UART... How to receive?

Question asked by Massimiliano Sturla on Sep 30, 2014
Latest reply on Oct 2, 2014 by Massimiliano Sturla

Hi, I'm stuck on the UART - RX ....

I'm using FRDM-K64 demo board and MQX 4.1.1

From user config I'm set a new (ttyb) UART, the UART1.

I correctly send data from K64 to my PC via serial port, but I have problem with receive routine...

I can read the receive buffer with this function (from rs485 example NOT for frdm-k64 but for one TWR)


fread(data_buffer, 1, 18, ttybSci1_dev);


where ttybSci1_dev is name of my port. The problem is that I can read but MQX do not tell me when a packet (or a byte) arrive, like linux with the signal

i suppose RX interrupt are managed by MQX and redefined tham I bypass MQX routine that acquire the byte

there is, something similar SIGNAL in linux, that I can use? Something that alert me when a byte arrive?


/* For write I use: */

char data_bufferTR[] = "\nTaskRead";

write(ttybSci1_dev, data_bufferTR, strlen(data_bufferTR));


/* For read I use */

void   *semReceivedData;

if (_sem_open("SemaphoreForDataRX", &semReceivedData) != MQX_OK) {

   printf("\nOpening semReceivedData semaphore failed.");



if (_sem_wait(semReceivedData, 0) != MQX_OK) {

         printf("\nWwaiting for semReceivedDatasemaphore failed");



fread(data_buffer, 1, NumberByteReceived, ttybSci1_dev)

So I need how to give the semaphore semReceivedData when MQX receive a packet (or a byte and I  will join all in a packet)

Many thanks,