Clear UV roms

[pyrre]

Will some of these UV roms fit the purpose of writing kickstartfile to it and replace the kickstart chips in A1200?

[Doobrey]

Nope, those 27c010/020 are only 8 bit chips.
You need a pair of 27c200 (128k*16 bit) for the A1200.

27c400's can be used too.. either as a 1MB ROM, or just burn the image into it twice and use as a 512KB ROM.

[alexh]

You can also use 27C160 ones too, they are less friendly as you must bend two pins and solder them (to VCC or GND perhaps via switches) but they are more readily available, they can hold multiple kickstarts, but are slightly more expensive.

[Doobrey]

It's times like this I really wish I could mention a project by another Amiga.org member :sealed:
(unsubtle hint: pin compatible and a lot easier that faffing about with UV erasing ;-) )
Hopefully it won't be long before there's some news.

[hardlink]

Doobrey wrote:
27c400's can be used too.. either as a 1MB ROM, or just burn the image into it twice and use as a 512KB ROM.

In 1994, Kickstart chips in my A4000D were ceramic body EPROMS with the UV window, programmed of course with KS 3.0, and may have been 27C400's. Made it real easy to upgrade to 3.1

I have no idea why Commodore, already losing money, used IC's that were probably 10 times more expensive than the usual ROMs.

[lopos]

Doobrey wrote:
It's times like this I really wish I could mention a project by another Amiga.org member :sealed:
(unsubtle hint: pin compatible and a lot easier that faffing about with UV erasing ;-) )
Hopefully it won't be long before there's some news.

Tell us a bit more about that secret project. :violin:

[Hodgkinson]

Oooh, I just had a idea.

If you get ROMs/EPROMS that are much larger than what is required, then what you could do is connect all of the amiga address lines to the ROM address lines, except displaced by one or two address pins (Eg, A0 goes to A2, A1 to A3 etc, providing that this *larger* chip as two more address lines - In this example - Than the standard ROMs). This way, suppose you displaced the addresses by two pins, then you could have 4 different kickstarts programmed into the ROM / EPROM, selectable by applying voltages to the first two address pins.

This way, the 4 kickstarts would have there code staggered every fourth memory location (With a address pin dispalacement of 2).

One problem: I dont have a programmer. The largest amount of code I have ever programmed into a EPROM is 16 addresses, manually, using DIP switches on a protoboard. This EPROM is used as a LUT in a RC remote control converter. :-D

Hodgkinson.

[pyrre]

What is a LUT?

[Doobrey]

Hodgkinson wrote:

This way, the 4 kickstarts would have there code staggered every fourth memory location (With a address pin dispalacement of 2).

I'd do it the other way around, Amiga A2->ROM A0 , and use the top 2 address lines to switch between kickstarts. That way, you just have to join all the different images together instead of having to interleave them (plus if you use flash instead of EPROM you can replace a single ROM image without having to rewrite the entire chip)

[Hodgkinson]

@pyrre : A LUT is a "Look-up-table", a series of preprogrammed outputs for given address locations. In my case, a microswitch joystick is connected to the address lines, and the outputs connected to output transistors, which then in turn control the RC transmitter. I diddn't like the left motor/right motor controls on the transmitter, so I programmed the EPROM locations to convert the microswitch outputs to switch on the motors in the correct directions.
I also wired up a buzzer to warn of invalid combinations, eg, the left and right microswitches pressed at the same time, etc.
(I'll stop there before I skew off subject all together...)


Re Kickstart:
Hmmm. I suppose you could use the highest address pins. I was thinking that, depending upon the EPROM size, that using the highest address pins might inavdertently mean that one of the kickstarts at the end of the memory might have to be made smaller than all the others. Thinking on, chip sizes tend to be equal to the number of possible combinations of 1's or 0's on the address lines, so this might not be such a problem.

Flash IC's shouldn't be a problem either.

Hodgkinson.