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uartlite interrupt not working


Hi everyone,

I only posted this question after i tried everything I could. I am trying to use uartlite with microblaze and interrupt controller (nexysvideo board) to receive some data. I wrote a lot of variations but it doesnt seem to work. my simplest basic code was to turn on a led when a byte is received. building of the project is fine, no errors but nothing happens when runing in hardware. i also tried the provided example (uartlite_intrc_example) which ask for a physical loopback (my understanding is that i have to send back whatever data i receive in the terminal, but i m not sure, i m not a native english speaker) which also did not work. can anyone please point me on how to use the uartlite in this mode (not the provided examples unless i was misusing it). I do not even know if i am using the ip drivers and functions correctly. this an example of what i did:

#include <stdio.h>
 #include "xparameters.h"
 #include "xuartlite_l.h"
 #include "xuartlite.h"
 #include "xstatus.h"
 #include "xintc.h"
#include "xgpio.h"
#include "xil_printf.h"
/************************GLOBAL VARIABLES******************************/

#define LED_CHANNEL 1
#define LED 0x01

XIntc IntCntroller;
XUartLite UartLite;
XGpio  gLED;
static volatile int flag= 0;
//****************************functions prototypes******************/
void uart_int_handler(void *baseaddr_p);
XStatus initialize_system ();
XStatus initialize_system () {
   XStatus status = XST_SUCCESS;
     status = XUartLite_Initialize(&UartLite, XPAR_UARTLITE_0_DEVICE_ID);
     if (status != XST_SUCCESS) {return XST_FAILURE;    }

     status = XUartLite_SelfTest(&UartLite);
     if (status != XST_SUCCESS) { return XST_FAILURE;     }

      status = XIntc_Initialize(&IntCntroller, XPAR_INTC_0_DEVICE_ID);if (status != XST_SUCCESS) {return XST_FAILURE;    }
      status = XIntc_Connect(&IntCntroller,XPAR_INTC_0_UARTLITE_0_VEC_ID,(XInterruptHandler)&uart_int_handler, XPAR_UARTLITE_0_BASEADDR);
     if (status != XST_SUCCESS) {return XST_FAILURE;    }
       XIntc_Enable(&IntCntroller, XPAR_INTC_0_UARTLITE_0_VEC_ID);

       status = XIntc_Start(&IntCntroller, XIN_REAL_MODE);if (status != XST_SUCCESS) {return XST_FAILURE;    }
        status = XGpio_Initialize(&gLED, gLED_DEVICE_ID);
             if (status != XST_SUCCESS) {      return XST_FAILURE;      }
         XGpio_SetDataDirection(&gLED, LED_CHANNEL, ~LED);

          return status; }

void uart_int_handler(void *baseaddr_p) {

     while (!XUartLite_IsReceiveEmpty(XPAR_AXI_UARTLITE_0_BASEADDR)) {

       flag = 1; }     }

 int main () {

      while (1) {
          if (flag == 1) {
            XGpio_DiscreteWrite(&gLED, LED_CHANNEL, LED);

       }}  return 1; }


(just a side notice: what does the TX led LDI13 in nexys video board refers to? it's on when i send data over uart. i thought it should be RX for receiving data?)

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2 answers to this question

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Hi @nattib,

Here is an older tutorial that walks through setting up the uart with interrupts for the nexys video. Unfortunately it then only uses the hello world template in sdk. Here is a xilinx forum thread that has a gpio interrupt example.  I am not seeing anything wrong with your sdk code. I have not used the uart/gpio interrupts in this way. Also i believe the uart tx and rx are labelled from the pc's point of view and not the FPGA's.  

thank you,


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hi jon,

thank you for answering, now i know at least my code is correct. the tutorial you pointed to uses the hello world example , in which i didnt find any trace of interrupt use, at least explicitly. i ll see with the thread maybe it could lighten me up :). thanx anyway!!


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