ST536 in a Mega ST4

[stephen_usher]

Well, in that case it could be due to two things. Either the IDE device is taking too much power or, if the buffer chips aren't installed, something on those data lines is upsetting the system.

[HomeLate]

Well, in that case it could be due to two things. Either the IDE device is taking too much power or, if the buffer chips aren't installed, something on those data lines is upsetting the system.

So, best to get a buffered CF/SD-IDE adapter then. Both adapters I tried are unbuffered.

[stephen_usher]

It may help. It separates the FPGA from the IDE device, which is safer at the very least and it will be able to drive a longer cable as well.

Of course, if your IDE device is just pulling too much current the VCC voltage on the board will dip and the system become unstable. I know that it can't handle my Hitachi Microdrive in an CF-to-IDE adapter, so IDE spinning drives will probably pull too much too.

[HomeLate]

It may help. It separates the FPGA from the IDE device, which is safer at the very least and it will be able to drive a longer cable as well.

Of course, if your IDE device is just pulling too much current the VCC voltage on the board will dip and the system become unstable. I know that it can't handle my Hitachi Microdrive in an CF-to-IDE adapter, so IDE spinning drives will probably pull too much too.

Okay, I ordered one just now, the same I use in my A4000 (cough). I'm going to hook up my scope and monitor VCC on the board while testing the old and the new CF-adapter.

Thanks Stephen for the suggestions, everybody else too, I really appreciate the suggestions made here. I'll post my findings here after I have received the new CF-adapters.

[exxos]

The ST536 has IDE buffers on the bottom of the PCB...

I think the main question, is why IDE is seemingly triggering during ROM access causing the crashes, as GB6 doesn't use IDE other than loading GB6 itself.

[HomeLate]

The ST536 has IDE buffers on the bottom of the PCB...

I think the main question, is why IDE is seemingly triggering during ROM access causing the crashes, as GB6 doesn't use IDE other than loading GB6 itself.

If you leave the system idle, it will crash after 10 - 20 seconds. If I remove the IDE adapter, the crashes are gone.

[HomeLate]

To my surprise none of the buffered IDE adapters work

So, I tried an ACSI2STM next and the system is rock solid. I ran some games and a few GB6 loops and it never crashed. It's clearly an IDE issue. Can someone recommend a IDE2CF or IDE2SD adapter? I mostly tried Amiga ones and it feels like the Mega ST senses the Amiga logo on the PCB and therefore refuses to work with those.

[exxos]

As I said before, IDE causing a crash can only really be false IDE access when there isn't supposed to be one. Likely a bad solder joint on your PLD,. I assume one of the address lines or IDE control lines.

[HomeLate]

As I said before, IDE causing a crash can only really be false IDE access when there isn't supposed to be one. Likely a bad solder joint on your PLD,. I assume one of the address lines or IDE control lines.

I'm going to build a second one and order new parts next week. I'll order a smaller tip too to solder the PLD.

Does the speed of the PLD matter? I have a 5ns CLPD left, or else I order a 10ns one (which are cheaper).

[exxos]

I'm going to build a second one and order new parts next week. I'll order a smaller tip too to solder the PLD.

I suggest putting solder on the PLD pads first with flux, make sure they all plated with solder. Then use solder wick (with flux) and get the solder off again, make sure all the pads of flat before soldering the PLD. If you plate the pads with solder first, it will be a lot easier to solder and be more reliable.

Does the speed of the PLD matter? I have a 5ns CLPD left, or else I order a 10ns one (which are cheaper).

I never tried 5ns. I think they were really expensive. It's possible using a different speed grade could cause problems. But I would image it would cause SDRAM issues if anything. But it's not an experiment I have ever done. So I suggest you keep to the proper BOM parts.