DigicoolThings Forum

I had a horrible time getting this otherwise really simply board working and I'm still not entirely sure what fixed it. It got to the point where I reproduced the board in prototype form on a breadboard and I could communicate with the IO device but for whatever reason I couldn't do the same on the board. I tried cleaning the board, swapping chips, checking power, checking signals, checking for shorts - everything seemed fine but it just wouldn't work. I then took out the chip select signal from the board by soldering a wire to appropriate GAL pin and used it to select the prototype version (rather than using the prototype GAL) and it still didn't work ... I was just about to give up and so desoldered the chip select wire ... and then it started to work - I have no idea why

Anyway, the first prototype of the IDE interface appears to be running with RomWBW and the Z80 board (it is based on the RC2014 equivalent). I tested it with a compact FLASH to IDE adapter, the FLASH card has the RomWBW "combo" disk image. I tested booting CP/M 3 off it and that seemed to work OK. I wanted to have a right-angle IDE header so that I could plug the FLASH adapter on top (so it doesn't interfere with other cards when it is in the upright position) but it turns out that I had the connector the wrong way around - it didn't really matter as the IDE adapter doesn't have a guide on top (like the right-angle header has) - but it does have a "key" i.e. blocked pin in the socket to ensure the adapter is plugged in the right way around. I think the PCB-mount LEDs I purchased may also be the wrong way around compared to what I expected so the activity light on the board isn't lighting up (though activity is still shown on the FLASH card adapter). I haven't tested the standard 40-pin IDE yet. I may need another adapter to test that as I don't have any IDE drives.

I've uploaded my current version of the IDE card over here:
https://github.com/epaell/MECB/tree/main/MECB_IDE

I'd suggest holding off from generating boards until I get an updated version of the board done.

I've received the v1.0 boards now and they seem to work fine. I've updated my GitHub with the design files and also the PLD definition.

https://github.com/epaell/MECB/tree/main/MECB_IDE

The one bit I haven't tested yet is the 40-pin IDE interface. It "should" be identical to the 44-pin interface apart from missing the power lines (those are supplied via a separate power cable).

OK, managed to check the 40-pin interface as well (I had a Compact FLASH interface on an old 486 PC that had the 40-pin adapter ... I just had to make an appropriate power cable for it). I had never previously noticed that this cable also had pin 20 blocked (to act as a key - despite having the guide on the connector) - so I had to break it off on the PCB mounted connector. I've slightly modified the PCB to add a label to point this out and have also mentioned it on the GitHub readme. I've forgotten exactly how the IDE interfaces work but I suspect that only one of the connectors should be used at any time and then the master/slave set-up needs to be used to select which drive is which (but I could be wrong).

Not the most beautiful set up ... but finally managed to test two IDE drives connected to the same card. In this instance I had a Compact FLASH to 44-pin IDE adapter board (set up as a slave) and a Compact FLASH to 40 pin IDE drive adapter (set up as a master). I can't imagine ever needing so many drives but at least it can be demonstrated to work.