The interrupt routine would only be writing the next byte of audio to the DAC which would be at a fixed address, whats causing the corruption is that the CPU st

The interrupt routine would only be writing the next byte of audio to the DAC which would be at a fixed address, whats causing the corruption is that the CPU stores the state of the CPU when the interrupt occurs onto the stack; this isn't where the audio is being played from void execute_interrupt(void * isr) { // push the registers of the program running when // the interrupt happens onto the stack that's currently // in use. this is something the CPU looks after usually // (I think). // This meant in the article that the contents of the // registers were being pushed to the buffer holding // the current image, overwriting whatever data was // above the stack pointer. The fix was to swap which // register was the source and which the dest, so that // the ISR would be pushing to the buffer that was about // to be written to. pushRegs(); // do whatever's needed to get the CPU into a consistant // state for the ISR zeroRegs(); // call the interrupt service routine for whatever interrupt // has occured isr(); // just decrements the system stack pointer, leaving // whatever was above the point corrupted in the // original version using the two stack regs popRegs(); }