I have a debugging issue that you guys may be able to shed some light on. The device is an audio player on a custom PCB. It receives commands from a radio link via UART and plays audio files from an SD card based upon the commands it receives. The controller is a 1284P which reads mp3 files from the SD card and stores the data in a buffer. It then feeds the data via SPI to a VS1063 audio processor that decodes and plays it.
The problem I am having is that this system will not work under the control of AS7's debugger, but it works fine running by itself. When it is running free, it will play a file to the end. However, when I start a debugging session(JTAG ICE), it sends the data to the DSP, but the DSP won't play it. I suspect that the problem is related to timing. The DSP calls for data by pulling up its DATA REQUIRED line that is connected to a GPIO pin on the 1284P. The 1284P waits for the DATA REQUIRED line to go high and then sends 32 bytes to the DSP. It repeats this till the end of file. When its free running, the DSP calls for data every few milliseconds from the beginning to the end of the file. But when I start a debugging session, there is no activity at all on the DATA REQUIRED line.
I would not think that the DSP would know whether there was a debugging session going on or not. Whatever the cause, I notice that once I start a debugging session, I have to reboot the MCU to get it running normally again.