EEPROM Programmer V2.0 (for real)

[dracosilv]

I was finally able to get around to re-create my EEPROM programming cart:

http://flickr.com/photos/10993712@N05/3143907677/


http://flickr.com/photos/10993712@N05/3143907707/


Tell me what you think!

Questions/comments welcome!

[Richard James]

What does it do? You say it is a "EEPROM programming cart" does that mean the VIC20 is programming the EEPROM or it accepts EEPROMS that have been programmed by a PC?

[dracosilv]

What I mean by 'EEPROM programming cart' is that the VIC-20 can write the EEPROM (5v VPP PARALLEL EEPROMs only), or, with a small adapter (for slightly different pinouts of RAM/ROM chips) i could read other chips and/or test a SRAM.

In a nutshell the chip is acting as a bit of RAM (or ROM) in the /BLK5 area.

I think, in the future, I will add some other pieces of cabling/adapters to allow me to change what block it's set up as and maybe even a simple mod to allow me to 'write protect' an EEPROM chip I'm working on filling with routines/data.

[Leeeeee]

IF you try to program EE or flash devices using BASIC there is a gotcha about POKE that you need to be aware of.

See here.

Lee.

[dracosilv]

I assume that the following code doesnt' have the same problem?

Code: Select all

LDA $1000,X
STA $A000,X
LDA $1100,X
STA $A100,X
etc?

[Leeeeee]

That should be ok.

Absolute indexed addressing is ok as long as there is no page crossing so any LDA/STA $xx00 will be fine. However if the page boundary is crossed there will be a spurious read at the final address - $0100 for both LDA and STA.

Lee.

[dano]

I'd be interested in one if it came with some a software package and was useful without too much hacking

[dracosilv]

Well, what would you like in a software package?

/me might try creating software for the chip. (Not a guarentee, but it would be something I could work towards creating for my adapter.)

Also, it doesn't really require all that much 'hacking'. the main 'hacking' that would be needed would be the addition of:

The R/W line,
1 inverter (7400) so that the /OE (Output Enable) line is inverse of the /WE (Write Enable) line,
and the re-ordering of the 23XX style pinout to the 27/28XX style.

[dano]

Hmm, good question. I guess I see two uses for such a thing. One is something similar to an EPROM programmer, where I could load a .hex or .bin file from disk, write to EEPROM, verify, and then use that chip on another platform, project, whatever. The other, is just a programmable cartridge, where I could download a ROM dump of a game or any program that can run from ROM, and write it to EEPROM. Something similar to this:

http://www.atarimax.com/flashcart/documentation/

I guess by "hacking" I ment that I'd like to avoid writing my own code to program the EEPROM, at least initally I would *love* to make my own Disk Menu V23 cartridge, for example.