I've 'inherited' a custom board (with schems and datasheets etc, thank God!). I've never done any embedded work at all really and I've been having a play with this, with a little success.
What I have a is a custom bootloader (S-Record, no source) and a RAM loader tool for the board. As I understand it, I basically set the board to Bootstrap and the RAM loader is a set of Bootstrap Records which setup some basic functionality like Chip Selects etc. We then load in our Bootloader S-Record which then has lots of fancy options for doing things like turning on the LCD screen, printing test patterns, poking memory addresses etc. It also has an option to run code from a memory location that you give it.
By adding Bootstrap Record lines to the RAM Loader, I've managed to do things like switch the LCD backlight on, switch the LCD display on and even display a pattern on the screen. Using Easy68K, I've written some ASM that performs the exact same operations as my Bootstrap Records (change THIS register to THIS value). This code runs fine in the Simulator and all the memory addresses are changed as I'd expect. When I run it on the board itself, it just hangs. I'm not sure whether (for example) I need to include a STOP or RTS at the end of the code to complete operation or a jump back to the memory address of the original code.
Basically, I'm looking for any ideas about the above as well as any recommendations for books, online tutorials, code examples (especially code written for the Motorola MC68VZ328 ADS dev board) and just any pointers and tips at all to help a complete newbie get started!!
Replies to email or the board will be fine. Thanks in advance for any help/support I get!!