>For the Q40, low RAM is either read only or write only and it is normally read >only. To write to low RAM you must poke a byte address (I think any value will >do, but I use $FF). Interrupts must be disabled while doing this. Why? There's >a prize for the first person who posts the correct answer to the list.
If interrupts are not disabled the interrupt handler will be called while the low memory is write only, and as the interrupt handler code is probably in the low memory zone, the code to be executed cannot be read. This would result in a complete crash of the system (either immeditely or because the exception handling routine is also in low read only memory). Just my guess. Joachim
