Posted on May 17, 2011 at 14:14What's the best way to debug? I mean, I'd like to know if the timer is running.
This will depend a lot on the equipment you have. I'd have the timer output on a pin, and check it on an oscilloscope, but I'm more interested in fine granularity timing. For 1/4 Hz or slower toggling an LED works fine for visual inspection.
You could also snap shot the CPU instruction cycle counter at the interrupt, and print it out to the serial port in a foreground task. This would provide a fine grain measurement of period and interrupt latency.
You could count the observed interrupt, print that out once a second.
You should be able to breakpoint the timer interrupt handler with a USB JTAG pod (J-Link for IAR), you can in Keil, but at least one forum member has claimed this is not possible in IAR. Kind of doubt that, but whatever. Break points will however mess with the periodicity.
The STM32VL Discovery board includes a STM32F100 and an ST-LINK JTAG debugger. It has a couple of LEDs, and easy access to the GPIO pins. Costs ~$10 + shipping. They are good for checking/validating code and ideas outside of a more complex board/project environment. They don't have an RS232 serial connection, which makes the a little less than ideal, but a lot better than some STM32 stamp boards without a proper JTAG connection.
