Open Hardware Kickstart Switcher for Amiga Computers
This release physically moves the EPROM further up, so that the shielding and keyboard sit in the proper place on A500s. Note that the shielding will still touch the EPROM, so it is recommended to put insulation tape on the contact point, but you should manage to put everything in place and close the case properly.
This release also exposes the A19 address pin when using a M27C160 EPROM. Since this part seems cheaper than M27C800s, you can use it, provided that you connect A19 to GND or VCC, depending on how you flash the EPROM: use GND if you flash the lower addresses, and vice-versa.
You can even use this feature to have SIX (!) Kickstart images on your Amiga: just wire another SPDT switch to A19 (center pin), VCC and GND: this way you will be able to switch among 4 256KB images and 2 512KB images, which is basically whatever you might EVER need (say: DiagROM, 1.2, 1.3, 1.4alpha, 2.05 and 3.1).
This version has been tested on an A500. I have used an M27C800-100F1 EPROM by ST and an SN74HC00 gate. While I don't recommend using parts from the HC series, functionality-wise the board works perfectly. The 100ns EPROM seems to be fast enough. Of course you are free to use faster EPROMs, but I would suggest to stay away from 150+ models: while they may still be fast enough, I can't guarantee that.
Since I am a Linux guy, I created the EPROM image file like this:
cat diagrom.bin kick13.rom kick31.rom | dd conv=swab of=oks.bin
256 KB ROMs go first and the 512 KB ROM goes last (See #1 for a 256 KB diagrom.bin). The files I used were in "UAE" format, that is low-endian. The dd bit will byte-swap the output file, so that it is big-endian and ready to be flashed on the EPROM as-is.
This release will probably also fit A2000s, while in A600s you still won't be able to reposition the keyboard. I don't know what can be done in this regard, space is really at a premium in the A600 :(.
This is the first release of this project. It has some issues, see below.
This version has been tested on an A500, A600 and A2000. I have used an M27C800-100F1 EPROM by ST and an SN74HC00 gate. While I don't recommend using parts from the HC series, functionality-wise the board works perfectly. The 100ns EPROM seems to be fast enough. Of course you are free to use faster EPROMs, but I would suggest to stay away from 150+ models: while they may still be fast enough, I can't guarantee that.
Since I am a Linux guy, I created the EPROM image file like this:
cat diagrom.bin kick13.rom kick31.rom | dd conv=swab of=oks.bin
256 KB ROMs go first and the 512 KB ROM goes last (See #1 for a 256 KB diagrom.bin). The files I used were in "UAE" format, that is low-endian. The dd bit will byte-swap the output file, so that it is big-endian and ready to be flashed on the EPROM as-is.
Now, to the bad news: the board has some physical issues that make it hard to fit in A500 and A600 computers. On the A500, the top shield will lean against the board, so it is recommended to put insulation tape on the contact point. The keyboard will also be slightly lifted wrt its normal position. You can manage to close the case, but it will be somehow crammed.
On the A600 the keyboard just won't fit.
On the A2000 it fits just nicely.
I'll think about a redesign of the PCB for the next release.