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1. #Pic and eeprom programmer circuit serial
2. #Pic and eeprom programmer circuit manual
3. #Pic and eeprom programmer circuit full
4. #Pic and eeprom programmer circuit code

This could be a spare bit on the parallel interface chip or a flip flop (e.g 74LS74) (and in the latter case you'll need some address decoding for it). Instead I'd recommend hooking it up to some kind of external latch so writing can be enabled and disabled as necessary.

You could hook it up in the same way as the RAM but doing so risks accidental writes to ROM which will cause undefined operation. In hardware terms you'll need to hook up the /WE pin on the EEPROM. You can do that by reading back the same memory location until what you read back matches what you wrote (maybe with a timeout in case the write failed).

#Pic and eeprom programmer circuit code

Instead you'll need to copy any code to RAM and run it from there.Īlso you'll want to wait until the EEPROM has finished the write for each byte. Which means you can't run your program code from ROM. The big gotcha will be that the EEPROM takes a few milliseconds to store data and during this time it isn't available for anything else. Look at the video from the 8-bit computer build where he programs the EEPROM from an Arduino. It would be very possible - as long as you're using an EEPROM which is programmable at 5V. There is more advanced version here as well: If you want to see this in action, it's here (80% of the page, "So, was it worth it?" section): If you want more details (and alternative approaches!), I wrote about it here: Bonus point is that you don't need the TL866 II+ programmer anymore - it's all sitting there on the board. Sure, it requires extra wiring (you have to suspend 6502 using RDY pin and disable its control over the bus using BE pin), but otherwise it's perfectly doable.

#Pic and eeprom programmer circuit full

Hey, there is another, very convenient option: remember, when Ben hooked up Arduino Mega to 6502 build for bus analysis? You can use it (or simple AVR chip, without the full board) also to write to the bus, and to write to EEPROM that way. The UART bootloader is what Dawid Buchald’s DB6502 implements, using the Rockwell R6551P ACIA.įinally, you always have the option of writing an assembler, adding a keyboard, adding video, and adding a microSD card adapter for persistence.

#Pic and eeprom programmer circuit serial

You could even get fancy and keep the serial port listening, and be able to send commands directly to the computer over serial (“go to a busy loop”, “load a new program”, “jump to address”, etc.) Then, switching programs is as simple as pressing Reset and transferring a new file over serial. You would want to change your address decoding so you have more RAM and less ROM in the address space. It holds RST low on the 6502 while it’s doing its work, and can be powered by either USB or the EEPROM power rails.Īnother option would be to add a UART, and program your ROM as a bootloader which reads a program over serial and then jumps to it. I’ve recently started using the EPROM-EMU-NG to replace the EEPROM with a second SRAM chip, along with an Arduino Nano and some shift registers to be able to program the SRAM from your development station. It also saysĢ、ATMEL89S51, 52, AVR ATMEGA full range, Note: High-voltage parallel programming, low-voltage ISP programmingģ、MICROCHIP PIC10Fxxx 12Fxxx 16Fxxx 18Fxxx full range,Ĥ、New Mao SYNCMOS SM59Dxx SM59Rxx full range of chips4.2.11Multi-machine programmingSoftware The EEPROM is parallel-programmed, but the ICSP header only supports serial programming.

#Pic and eeprom programmer circuit manual

Reading the instruction manual from XGecu, it doesn’t look like it.