I’m working on some ideas that may eventually evolve into a ‘front panel’ for my //e.
The proposed feature list (in descending order of likelyhood that I will have the time & skill to implement):
- A toggle to flip between a ‘standard’ ROM and a crack-ROM (most likely "Senior PROM")
- A debounced ‘NMI’ pushbutton
- A 4 digit readout of the current program counter
- hardware breakpoints (i.e. an address can be entered through a 4×4 keyboard, and when that address is executed, read or written, an NMI is generated).
- A ‘single step’ mode.
I intend to use one or more Atmega8 microcontrollers in this. Here are some relevant links so I can keep track of them:
- Using AVR microcontrollers: Minimalist target boards
- Building and installing USBASP-USB programmer of AVR microcontrollers
- Atmega8 datasheet (full version)
- Extended 7-segment font (I have burned this in to a 28c64, then wired D0..D6 of the 28c64 to the Segment A.. Segment G pins on a "common cathode" 7 segment LED display. Then sending a number between 0..0x0F on pins A0..A3 on the 28c64 causes the corresponding digit to be displayed).
- AVRDUDE manual
- First contact with ATmega8 microcontroller
- Online AVR Fuse Calculator