Problems burning Kickstart

[Computolio]

I've been trying to burn Kickstart 3.1 ROMs for my 1200. I took a (40.68) Kickstart 3.1 image, split it into even and odd words using WinHex, and burned the resulting two files to two 27C2048 EPROMs. I put them in the kickstart sockets and I get a blank screen when I turn the machine on. I've swapped the ROMs around and have always made sure to put them in the exact same way.

There's something I'm missing here, and I don't know what. The mask ROMs still work fine, and I'm guessing this is one of those cases where the mask ROMs have a slightly different pinout than the equivalent EPROMs.

Has anyone else tried this before?

[Jope]

The 27C2048 doesn't strike me as being the correct model to be directly plugged into the A1200 motherboard.

I seem to remember that the 256kB chip is the 27C200 and the 512kB chip is 27C400.. So you'll need a pair of 27C200s. Also perhaps a 23C2100 can be used as the 256kB chip and a 23C4100 as the 512kB chip..

http://www.rabayjr.com/Download/MXIC%2023c2100.pdf

It's becoming increasingly hard to locate these chips, I'd suggest you use a modern flash part and create a personality module to plug it into the Amiga.

[whiteb]

I can confirm, i have a KS2.04 for A500 on an MX23C4100-1001 (512K).

[alexh]

The amiga EPROMS have a different pinout to regular EPROMS. You do need 27c400's or clones.

Get 27C400's as they work fine in A1200's (half empty) and A500's.

You can get them 2nd hand from Europe for about €10 each

[DoctorQ]

Brilliant to pay €10 for each rom instead of paying 18 EURO for a legal set of roms....

[alexh]

Or buy them from America for $5 each including delivery?

[Computolio]

The EPROMs were free, pulled out of some broken-down UNIX terminal and erased. I should have caught the difference in pinout, that was really dumb of me. I'm really lucky I didn't fry anything.

Anyway, this is more a fun experiment than anything else.

[Computolio]

Seeing as how 27C200s are hard to find at the moment, would there be any problems in using 27c400s instead? What would the unused half of each ROM be filled with, and wouldn't they conflict with the Slow RAM address space?

[Jope]

Just burn it another time to the top of the chip if unsure. Otherwise tie the highest address line to ground with a jumper wire.

The chip won't magically overwrite your slow ram, as the machine will only address 512kB or ROM.. If the surplus address line is left hanging, there's no telling what the chip will give out at any given time (thus burn the image two times to fill the high half of the chip if you don't plan on making sure that the address line doesn't float).

[amethyst]

Computolio, what are you are using to burn your eprom?
Do you think something like this is suitable for the task?
http://cgi.ebay.co.uk/16bit-40-42pin...QQcmdZViewItem

I've seen lots of willem programmers on ebay and wondered if they can be used to burn kickstart roms.

[amethyst]

Answering my own question here, I think the willem eprom programmer is suitable for burning kickstart roms based on the info I found here:

Original kickstart rom device specifications:
A500, A1200 (MX23C2100)
A500+, A600 (MX23C4100)

Suitability of using Willem Programmer to burn kickstart roms:
http://www.willem.org/cgi-bin/yabb2/...1100593393/7#7
http://www.willem.org/cgi-bin/yabb2/...1120237226/0#0

Perhaps, the sockets on the 40/42 adapter should be replaced with ZIF sockets though.

[alexh]

I think you may require a converter board for the unusual pinout of the 27c400 chips. Make doubly sure as converter boards can cost more than EPROM programmers.

[amethyst]

Originally Posted by alexh

I think you may require a converter board for the unusual pinout of the 27c400 chips. Make doubly sure as converter boards can cost more than EPROM programmers.

The converter board (are you referring to the 40/42 pin adapter board) comes with it I believe. Here's the picture of it. This is a description from the sellers website. It supports these devices: 27C1024 (27C210), 27C2048 (27C2002), 27C4096, (27C4002),M27C400(DIP40), 27C800, 27C160, 27C322. You put the 27C400 eeprom in the 42 pin socket but start at pin 2 of the socket.

UPDATE:
Having investigated a bit further on some forums, I've changed my opinion of the Willem eprom programmer.
In particular the version of eprom programmer that is only powered through the USB port.
It seems to have problems providing the required voltage during the eprom programming stage, ie. Vcc should be around 6V but due to the flawed design it only provides about 5V. So I think this particular eprom programmer is one to avoid.

UPDATE #2:
I bought one anyway and it works

[amethyst]

For the A500, A1200: Comparing the pinouts of the MX23C2100 and the 27C400 from their datasheets. Pin 1 is the only difference between the two. MX23C2100 has this as a no-connection pin and the 27C400 has this pin as Address input A17. This must be what jope is talking about here:

Originally Posted by Jope

Just burn it another time to the top of the chip if unsure. Otherwise tie the highest address line to ground with a jumper wire.

The chip won't magically overwrite your slow ram, as the machine will only address 512kB or ROM.. If the surplus address line is left hanging, there's no telling what the chip will give out at any given time (thus burn the image two times to fill the high half of the chip if you don't plan on making sure that the address line doesn't float).

However, for the A600 and A500+, the 27C400 is identical pin-for-pin to the MX23C4100

[amethyst]

I bit the bullet and bought the Enhanced Willem Programmer (regardless of what I had read about them) and this particular programmer worked fine for me when burning kickstart roms using 27C400 eproms. I tested an eprom in my A500, A500+, and A600 and they all worked fine. I haven't tested one in my A1200 yet as it requires 2 eproms. Will test this soon as well.

Useful note: If you read a kickstart rom chip into the eprom programmer and want to use it in winuae you have to perform a "swap BYTE" operation and then save the file.

This eprom programmer will also come in handy for programming eproms for my C128 and Plus/4

PS. If you do have a choice between a USB only powered willem programmer and one with selectable power options i.e dual power, choose the dual power one.

[amethyst]

In answer to the Computolio's original question, here's how to burn a kickstart eprom set for an amiga a1200 in 4 easy steps:

Requirements

• Eprom Programmer (with support for 27C400)
• WinHex utility (registered version) or write your own code to perform Steps 1 to 2.
• Kickstart rom file being used in WinUAE (not encypted and legally created from your own set of A1200 kickstart roms, of course)
• Two blank 27C400 eproms

Step 1: Split the kickstart rom file
In WinHex select: Tools -> FileTools -> Dissect -> Wordwise (16-bit)
Select source kickstart rom file
Type in destination filename#1 eg. U6A_tmp.rom (00000-3FFFF for U6A)
Type in destination filename#2 eg. U6B_tmp.rom (00000-3FFFF for U6B)
Now you have two smaller rom files

Step 2: Fill addressable unused memory space for both eproms
Now, we're going to copy the contents of addresses 00000-3FFFF to 40000-7FFFF for U6A_tmp.rom
To do this, in WinHex select: Tools -> FileTools -> Concatenate
Type in destination file for a blank rom file to be created (eg. U6A.rom)
Append file U6A_tmp.rom to U6A.rom
Repeat this again, append source file U6A_tmp.rom to U6A.rom
Select Done and a message box will appear: 524288 bytes from 2 files were concatenated to "U6A.rom"

Repeat Step 2 using U6B_tmp.rom to create U6B.rom

Step 3: Burn the kickstart eproms
Start up eprom programmer software with 27C400 device selected.
Load U6A.rom to the buffer
Perform a swap BYTE operation on the buffer contents
Insert a 27C400 eprom into the eprom programmer and burn buffer to the eprom.
Apply opaque sticky label over the eprom window and mark it "U6A"

Repeat Step 3 for U6B.rom, marking it "U6B"


Step 4: Install eproms into A1200
Insert eprom U6A into U6A socket and eprom U6B into U6B socket (make sure the eprom has correct pin connections and orientation).
Power up and hey presto it works!

For more details on opening up your amiga and installing the eproms read the amiga kickstart guide from aminet.

[amethyst]

Here's how to burn a kickstart eprom in 2 easy steps

Requirements

• Eprom Programmer (with support for 27C400)
• Kickstart rom file being used in WinUAE (not encypted and legally created from your own set of A500, A500+ or A600 kickstart roms, of course)
• One blank 27C400 eprom

Step 1: Burn the kickstart eprom
Start up eprom programmer software with 27C400 device selected
Load the kickstart rom file to the buffer
Perform a swap BYTE operation on the buffer contents
Insert the 27C400 eprom into the eprom programmer and burn buffer to the eprom.
Apply opaque sticky label over the eprom window and mark it with version

Step 2: Install into Amiga
Insert eprom into socket (make sure the eprom has correct pin connections and orientation).
Power up and voila it works!

For more details on opening up your amiga and installing the eproms read the amiga kickstart guide from aminet.

[gizmomelb]

thanks amethyst - extremely userful info!

any hints/tutorials on burning a ROM for an Amiga 3000 please?

[amethyst]

Originally Posted by gizmomelb

thanks amethyst - extremely userful info!

any hints/tutorials on burning a ROM for an Amiga 3000 please?

Here it gives the following info
for the A3000: U180 (D0..D15), U181 (D16..D31)
for the A1200: U6B (D0..D15), U6A (D16..D31)

So I assume that the A3000 must have two 16-bit rom sockets: U180 and U181, like the A1200. Not having an A3000 to test, my guess is that you would peform the same steps for burning a kickstart eprom for the A1200 except that the eprom for U6A would be U181 and the eprom for U6B would be U180.

[gizmomelb]

thanks amethyst!