DIY AMIGA Kickstart ROM Switcher ( Time to move on ).
DARKAGE, you woke up the bear!!! No I gave up on switcher coming from your homeland (Australia). Appears they haven't learn things like Epacket Service.
Today the Ebay Seller and I have decided the package with the ROM switcher isn't ever going to arrive. Formal case started with Australia Post.
Paypal and the Post Insurance should take care of things money wise, but much time lost.
I've decided to build my own Kickstart ROM switcher to start up the project again.
I actually finished that Aquarium DOSER Build so have time.
Here is the
Aurdino Aquarium Doser Test Running on Your Tube (if Curious)
https://www.youtube.com/watch?v=TFAtzBtKVhA&t=26s6 Month project, but this Amiga Project became a un-planned disruption.
Most of the time was the User Friendly/FaultSafe Coding which you can see some of the results in the Video.
SO for short term. I'm building a SIMPLE Switcher. Just using a switch or Jumper.
Got some of these parts today. Most are my China Aliexpress Collectables.
I have a few options for how it will be built (Sockets, Risers, Connectors, Switch or Jumpers)
To save on massive (hand wiring) effort with a wirewrapper, or even bigger effort/cost to design and etch a PC board.
I found some cool
Ardiuno Interface Breakout-Board/Header Circuit Boards that have
40 Pin sockets points, with a
header for a
40 wire ribbon cable.
I bought them unassembled, for building options. $6 CDN each.
http://www.technologicalarts.ca/shop/store/details/508/13/adapters/adapter,-40-pin-dip-socket-to-ribbon-cable.htmlI got these a while ago to use them as an Extension for the Switcher, but looking at the designed, I can use them TO MAKE A SWITCHER.
I'll eventually add some Nand Gates, and make it a more intelligent switcher, but for now,
THIS IS THE PROTYPE concept.Basically like all/most memory chips there is a
CE(Chip Enable PIN) and
OE(Output Enable PIN). DECODING Address from CPU fetch, activates the ROM/RAM, etc.
The ADDRESS PINS and DATA PINS can all be connected to the MotherBoard ROM SOCKET. ROM only wakes up on CE signal.
The AMIGA Kickstart ROM socket is already decoded on either (CE, OR or Both) with the appropriate address lines for ROM range.
I will try CE first.
So I'll plug in the DIP SOCKET Adapter into the MOtherboard ROM DIP. Cut the CS-PIN on the adapter/DIP and route through a jumper or switch to send CS-from MB to the appropriate ROM of choice.
I find it astounding that nobody has documented this anywhere in the Forums (much more).
I had to research and figure this out myself. Having done that thesis on Eprom Burner helped. Plus this GERMAN thread was handy to confirm my thinking
http://www.a1k.org/forum/showthread.php?p=100270The Primary ROM will be plugged into the MB ROM SOCKET so close. The 2nd Rom will be via a short ribbon cable, so should be ok for Clocking Speed Noise.
The Jumper (for the CE broken connection) has to be fairly close to ROM to avoid NOISE. I will eventually buffer via NAND Chips, so I can extend the Jump to be a switch.
May need a Power Pin Capacitor, and possibly a Resistor or two.
If it works, then I may even expand and make it 4 ROM, since I have KS 1.2,1.3,2.2,3.1 ROMS.
Eventually if I wish, I can build extra logic to choose the ROM via ALT-ALT-AMIGA(KEYBOARD) which would be driven via the RESET pin of 68000 CPU CHIP.
That would need no external Mechanical switch. But I'd rather go 4 ROMs with switch out of CardSlot-Port, then 2 via keyboard.
THIS SIMPLE VERSION IS Near ZERO RISK to the Motherboard, so I'm ok doing it.