My KSRS V2.0 - strange operation on A600 with 1.3 ROM...

[1985BMWK75]

Hi all,

I posted about this on AmiBay, but since I am a "Trader" there, my posts are only available to members. There is not much traffic to my posts in the AmiTrader section, so I thought I would post here too. Anyones thoughts would be much appreciated. Hopefully things will work as they should (and as they do on my A500 Rev 6A MB). Here is my post from Amibay:

"I got my A600 KB today :-D The A600 ROM socket behaves much the same as the A500. The pin that I need to go low to high when CTRL+A+A are held does just that. KSRS V2.0 works on the A600 too. But, there is a very odd problem, that is very puzzling indeed...

I could only get it to work with a KS ROM 2.0 (the original A600 ROM), and a 3.1 ROM. If I used a 1.3 ROM, nothing, a blank screen. I could still switch back and forth, and it would work with the KS 2.0 or 3.1, but if I switched back to the 1.3, nothing. Now here is the weird part - if I plug the 1.3 ROM into the ROM socket on the MB, it works no problem!

Here are my thoughts on what might be going on. Looking at the ROM's, it looks like the 1.3 ROM is a 200ns part, and the 2.0 is a 100ns part (is that right?). The 3.1 ROM I have is a 150ns part - I know that for a fact, as I peeled back the sticker a little to check. I noticed that the 3.1 ROM took quite a while to boot the Amiga, whereas the 2.0 ROM was much faster (expected, due to the speed difference). I know what you're thinking - the 1.3 ROM has been slowed down even further (signal) by the extra "wire", of both the IDC cable, and the copper tracks on the PCB...but the IDC cable was only 10cm long, and I shortened it to 4cm. And then there is this fact - everything worked great with my KSRS V1.0. When I tested that, the IDC cable was 16cm long! The tracks on the PCB of KSRS V1.0 are also 0.30mm wide (but they are 70um thick, not the usual 35um). The tracks on the KSRS V2.0 PCB are 0.40mm wide (wider then on KSRS V1.0) and also 70um thick. The problem is the same with the prototype, so it's not a fault in one of the switching IC's. Both the prototype and KSRS V2.0 PCB work flawlessly on my A500, with any combination of ROM's. Anyhow, I'm thinking that the 1.3 ROM is just a little too slow for the A600 MB to use, when used with my KSRS V2.0. If my design was corrupting the signals somehow, why do the other ROM's work fine? Remember, the 1.3 ROM works when used in the normal manner, by itself. So it may be a combination of the slow ROM speed and my KSRS V2.0 that is causing the issue? If it was purely my KSRS V2.0, then no ROM should work?

Does anyone have any idea what the devil is going on? Is the A600 much more sensitive than the A500 - i.e. tighter tolerances and such? This is a real brain-buster for me!

The only other thing I can think of is that perhaps the IDC displacement connectors I use are not as good as a soldered wire? Although they look nicer, and save me a lot of work, are they technically inferior to soldering each wire? But still, why the devil does it work beautifully on my A500 Rev 6A MB, and then misbehave on my A600?

I have an EEPROM programmer on the way to me, and some blank OTP MX ROMS (new, of course - or they would be useless!), which are 120ns parts. I am hoping that once I make a backup of my 1.3 ROM onto the faster ROM, everything will work as it does on my A500."

Nathan

[da9000]

Not really what you're asking/looking for, but I know I've had problems with A500, A600 and A2000 with slow (200ns I think - I'll have to check again) KS3.1s. It'd get blank screens or a couple color switches and LEDs blinking and resetting.

[1985BMWK75]

The KS 3.1 ROM that is a 150ns part, boots the A600 no problem - it's just very slow do do so (until the boot screen appears with the disk etc). It is slow both in my KSRS V2.0, and by itself in the ROM socket. It is the KS 1.3 ROM that is causing me grief :-(

I just made a KSRS V1.0 for a guy in Holland, and tested it (again) on my A600, and it boots just fine from any rom, even the 1.3. The IDC cable length of that model is 10cm. Granted, it is switched via a mini toggle switch, and works on a similar, although different principle to KSRS V2.0.

I received my EEPROM programmer today  :-D I'll burn a backup KS 1.3 onto my blank ROM, which is a 120ns part. Hopefully that will cure the misbehaviour of KSRS V2.0 on my A600.

Nathan

P.S. If you are burning ROM's for your Amiga, I would not use anything slower than a 150ns part. 100-120ns would be ideal for any application I imagine ;-)

[da9000]

I know you are talking about KS1.3. I just meant that even KS3.1 @ 200ns would not boot for me, so perhaps that's why your KS1.3 won't once it's in your KSRS (even though it works when put straight in the 'migy, or for the Dutch guy...)

[trip6]

As I recall Kickstart 1.3 rom isn't supported by any amiga with an AGA chipset. Also the A600 requires a KS with built in ide drivers such as KS 2.05 or KS 3.1 which are the only two KS that will work on an A600 I believe...

[darksun9210]

hold on a second, a though is my brain entering....

the KS 1.3 chip i have... no wait.. is it 1.2? anyway either or. the point i'm trying to make is, that it came from a rev5 A500, and to get 3.1rom working in a rev5, i had to do a little wiring. lift pin one out the socket, run a wire from hole 1 to leg something, run a second wire to some other chip leg socket combo, do a little dance, put a teapot on your head, and tadaa! it fires up wit 3.1

if the 1.3 chip came from a rev5 A500, would you not have to do the reverse wiring to get it to work in a "standard" rom socket? :-?

[1985BMWK75]

Thanks for all your comments :-)

The KS 1.3 ROM works just fine in an A600 MB, you just lose the IDE and PCMCIA functionality. It just doesn't like working on my A600 when it is in my KSRS V2.0 :-(

Regarding bridging two pins on the ROM, that is for older REV 3-5 MB (A500, and maybe others?). It is pin 1 & 31 that are connected. My KSRS V1.0 & V2.0 do this with a jumper, which is either on or off. That's why I say they are compatible with all MB revisions.

I tested 33 out of the 100 "blank" OTP ROM's I bought so far. Every single one of them, although they look brand new, have been used :-( They all have data on them :-( They have not been painted, I checked with acetone. The pins on the legs are even bent outwards, like a new IC :-S Hopefully just ONE of them is blank, so I can burn the KS 1.3 image onto it. I have a feeling that if I can use a faster ROM, that will solve the problem with using a KS 1.3 ROM in my KSRS V2.0 on my A600.

Nathan

[rkauer]

 There is an utility program on Aminet called "grabSCSI" who solves the problem (partially) of no SCSI.device on pre-37300 kickstarts.

 Just run it from a floppy and it "remus" the SCSI.device from the running ROM and toss it to disk. Then is easy to just load the device from a boot floppy into any WB revision you have/want to run. :-)