matrix.show() not working in interrupt routine

[kanadagermane]

Hey,

I am using this library with an Adafruit MatrixPortal M4 and PlatformIO.
Since I do blocking HTTP requests with WiFiNINA (adafruit fork), I thought I can update the matrix in an timer interrupt to be able to do a scollable text.

I am using the SAMD_TimerInterrupt library for the interrupts:
SAMDTimer ITimer0(TIMER_TC3);

Unfortunately, the program execution crashes if I call matrix.show() in the TimerHandler. The setCursor() and print() methods do not lead to a crash.

`void TimerHandler0()
{
static uint32_t curMillis = 0;

curMillis = millis();
if (curMillis > TIMER0_INTERVAL_MS)
{
matrix.fillScreen(0);
matrix.setCursor(textX, textY);
matrix.print(str);
if ((--textX) < textMin)
textX = matrix.width();
matrix.show();
}
preMillisTimer0 = curMillis;
}`

Please let me know if you need anything additional from me.
Maybe there is even a better way of doing HTTP requests during an scrolltext, but I was not able to find a way of doing async http requests with the MatrixPortal.

Thanks in advance and best regards,
Daniel

[aiweier1231]

Hi kanadagermane,

You can integrate FreeRTOS or any real time OS to ur project ot achieve this. Making HTTP request and LED Matrix display two separate tasks.

[kanadagermane]

Thank you so much for this reply, you made my day!
For sure that was exactly what I was missing.