Using a timer when running a C program as 'bare metal'

one way is to use the axi_timer IP. you must add this to your design using XPS. In SDK when you creste the BPS you should get the scutimer_v1_02_a library under ps7_cortexlibsrc.

in your app source:

#include "xil_types.h"
#include "xtmrctr.h"
#include "xparameters.h"

The API you want to use:

tunsigned int time1, time2, cum_time;

     Status = XTmrCtr_Initialize(&TmrCtrInstancePtr, XPAR_AXI_TIMER_0_DEVICE_ID);
     if (Status != XST_SUCCESS)
     {
         return;
     }


t time1 = XTmrCtr_GetValue(&TmrCtrInstancePtr, 0);
t XTmrCtr_Start(&TmrCtrInstancePtr, 0);

// your process

t XTmrCtr_Stop(&TmrCtrInstancePtr, 0);
t time2 = XTmrCtr_GetValue(&TmrCtrInstancePtr, 0);

This gives you clock ticks, so if your clock tick is 10 ns, divide by 100 to get us.

i found that i had to reinitialize the timer for each measurement. i would be interested if you figure out why.

hope this helps.

I followed your instructions, but it seems like xtmrctr.h can't be found in the directory. What do you suggest to do here?

do you have tmrctr_v_2_04_a in your BSP ps7_cortexa9_1libsrc?
did you add an axi_timer in XPS and then redo the BSP for the modified HW?
I think you should get the library in BSP.
What libraries do you get?
scutimer but nor timrctr? i got both but maybe i did somehting different.
we'll get this sorted out -- no worries!

Hi, thanks again for your reply. Got all the include files worked out now :)

But when I try to run the program, it "stops" after checkpoint 3 (see code). The program doesn't terminate, but it uses several minutes with nothing happening.

The code has no errors or warnings. When I start the program I get the message: "FPGA configuration is not done on the target. Do you still want to continue launching application?"

Do you have any idea what I might do here?

Again thanks for your answers, much appreciated :)

Anders Viken



Code:
#include "xil_types.h"
#include "xtmrctr.h"
#include "xparameters.h"
#include<stdio.h>

int main()
{
tprintf("Checkpoint 1
");
tXTmrCtr TmrCtrInstancePtr;

tprintf("Checkpoint 2
");
tunsigned int startTime, endTime, usedTime;

tprintf("Checkpoint 3
");
tXStatus Status = XTmrCtr_Initialize(&TmrCtrInstancePtr, XPAR_AXI_TIMER_0_DEVICE_ID);

tprintf("Checkpoint 4
");
tif (Status != XST_SUCCESS)
t{
ttprintf("Problem with timer initialization. Exiting.
");
ttreturn 1;
t}

tprintf("Checkpoint 5
");
tstartTime = XTmrCtr_GetValue(&TmrCtrInstancePtr, 0);

tprintf("Checkpoint 6
");
tXTmrCtr_Start(&TmrCtrInstancePtr, 0);

t// the process
tprintf("Hello World
");

tXTmrCtr_Stop(&TmrCtrInstancePtr, 0);
tendTime = XTmrCtr_GetValue(&TmrCtrInstancePtr, 0);

tusedTime = endTime - startTime;

tprintf("Number of ticks used: %d
", usedTime);


    return 0;

}

As far as the FPGA configuration, I can help you there. First, make sure the hardware server is running (Xilinx Tools->Launch Hardware Server) and then select Xilinx Tools->Program FPGA. You'll have to select a bitstream. Zynqgeek's Hello_world walkthrough can show you how to get that if you don't have one. That should get rid of that error.

When I run your code, it goes from checkpoint 1 to 2 to 3 then repeats main from the beginning. Apparently the XTmrCtr_Initialize function (at checkpoint 3) isn't acting as you think it is/should. I'm interested in getting this working too so I'll also be working on it.

I found where the problem is, but I'm not sure how to fix it...

In the XTmfCtr_Initialize() function, theres a for loop:

for (TmrCtrNumber = 0; TmrCtrNumber < XTC_DEVICE_TIMER_COUNT;
t     TmrCtrNumber++) {
tt/*
tt * Read the current register contents and check if the timer
tt * counter is started and running, note that the register read
tt * is not using the base address in the instance so this is not
tt * destructive if the timer counter is already started
tt */
ttStatusReg = XTmrCtr_ReadReg(TmrCtrConfigPtr->BaseAddress,
ttttt       TmrCtrNumber, XTC_TCSR_OFFSET);
ttif (StatusReg & XTC_CSR_ENABLE_TMR_MASK) {
tttprintf("********** Timer %d already started **********

", TmrCtrNumber);
tttreturn XST_DEVICE_IS_STARTED;
tt}
t}

The description is "Check each of the timer counters of the device, if any are already running, then the device should not be initialized. This allows the user to stop the device and reinitialize, but prevents a user from inadvertently initializing."

Within this loop, I think there's an interrupt being fired, which is resetting something, and causing the program to go to the top of main(). I'm not sure how to overcome this, as it continues to happen during ever iteration. Could it be another timer that's firing the interrupt? I'll continue to look into this.

(If the code above doesn't format nicely, I'll repost it)

I tried installing the 14.5 xilinx package. then the program worked as intended :)

I have no idea why...

Anders Viken

do you get the printf message?
It sounds more like it is transferring execution to something uninitialized -- bad code. i think somehow your timer is not instantiated properly from the hw configuration.
what is the deviceid? if you only have one timer -- it should be 0. i hardcoded 0 in subsequent calls -- not good practice. but the deviceid passed to the function, XPAR_AXI_TIMER_0_DEVICE_ID was 0 in my xparamters.h file. if you passed something else, it could be reading some inadvertant location causing erratic behavior.
good luck.
freertos has timers that i have not used, so does the scutimer library.

good for you. i am just installing 14.4.
and keeping 14.2 around for the speedway course makes 3. this is too much space on my SSD!

I also use XPAR_AXI_TIMER_0_DEVICE_ID (which is a macro, defined as 0 in xparameters.h). It never gets to the printf statement. I'm not sure what's going on... I'll try freeRTOS or scutimer... Or maybe just reinstall v14.5