exxos's Atari, Amiga & retro forum

Okay, here we go with my build progress...

First up had to wait a bit longer for my OSHPark order as they missed the silkscreen on the first AfterDark run. New PCBs with silk screen arrived today. So I have 2 sets of PCBs now, some without silkscreen and some with. Will build one with silkscreen first.

Got my XILINX CPLDs from AliExpress so will need to check these are usable.

I am planning to test it in my H4 or H5 board so assume I may not need the RNs on the 68000 lines. Have just placed a Mouser order for these RN and a few other bits I needed.

Photo coming soon...

Top components solder in place and beep tested the pins on the CPLD confirming no solder shorts between pins.

Oscillator was too small but have managed to solder it in place.


Just need to solder R2 on the bottom.

Looking really good. Nice to see all the different color on these boards. Everyone seems to choose a new one each time. Remined me to get a few more pics on my progress uploaded.

kodak80 wrote: 11 Jun 2022 00:18 I am planning to test it in my H4 or H5 board so assume I may not need the RNs on the 68000 lines. Have just placed a Mouser order for these RN and a few other bits I needed.

Looking good!

Yes, shouldn’t need most of the RNs for a an H4 or H5 (or ST with the mandatory fixes done), but later firmwares do need RN11 populated, else you’ll have to bodge a pull up on one of the test points (I forget which) as it’s used to switch 16 and 8MHz modes.

BW

@Badwolf Might be worth documenting about the resistor network requirements here https://exxosforum.co.uk/forum/viewtopic ... 112&t=5471 As it's just random luck I was reading this post :)

Have added it explicitly to the readme:

https://github.com/dh219/DSTB/blob/main/README.md

Ta,

BW.

Badwolf wrote: 13 Jun 2022 10:25 Have added it explicitly to the readme:

https://github.com/dh219/DSTB/blob/main/README.md

Ta,

BW.

Just to confirm, your video shows 10k RN11, would 4.7K work as I didn't order a 10K in my Mouser order?

kodak80 wrote: 13 Jun 2022 12:53

Badwolf wrote: 13 Jun 2022 10:25 Have added it explicitly to the readme:

https://github.com/dh219/DSTB/blob/main/README.md

Ta,

BW.

Just to confirm, your video shows 10k RN11, would 4.7K work as I didn't order a 10K in my Mouser order?

Yep, 10k is purely nominal. They're just pull-ups so you can tie pins to ground to select the 'other' option.

At this moment that's limited to TP3 which, when tied to ground at reset, switches to 8MHz mode.

I advise people who want to do that to use a 220 resistor, or thereabouts (this is because different firmwares do different things on the test points, and this will avoid a short to ground). The only real limit on the pull-ups, therefore, is making sure the voltage divider provides a CMOS 'low'. I'd say anything from 3k3 to 10k would be fine.

Ta,

BW

kodak80 wrote: 11 Jun 2022 00:18 Okay, here we go with my build progress...

First up had to wait a bit longer for my OSHPark order as they missed the silkscreen on the first AfterDark run. New PCBs with silk screen arrived today. So I have 2 sets of PCBs now, some without silkscreen and some with. Will build one with silkscreen first.

Got my XILINX CPLDs from AliExpress so will need to check these are usable.

I am planning to test it in my H4 or H5 board so assume I may not need the RNs on the 68000 lines. Have just placed a Mouser order for these RN and a few other bits I needed.

Photo coming soon...

Was wondering if the CPLD from China worked for you and if you encountered problems with this upgrade in your ST ATX build?

Oldskool wrote: 01 Mar 2023 11:57

kodak80 wrote: 11 Jun 2022 00:18 Okay, here we go with my build progress...

First up had to wait a bit longer for my OSHPark order as they missed the silkscreen on the first AfterDark run. New PCBs with silk screen arrived today. So I have 2 sets of PCBs now, some without silkscreen and some with. Will build one with silkscreen first.

Got my XILINX CPLDs from AliExpress so will need to check these are usable.

I am planning to test it in my H4 or H5 board so assume I may not need the RNs on the 68000 lines. Have just placed a Mouser order for these RN and a few other bits I needed.

Photo coming soon...

Was wondering if the CPLD from China worked for you and if you encountered problems with this upgrade in your ST ATX build?

I built a PCB up using one of these chips but the RAM chip got hot when I powered it with 5v from my bench power supply. This was a while ago now and if I remember correctly the XILINX chip programmed using my Pi so it looked promising that the chips work but with the RAM chip getting hot, I put it aside for when I had time and energy to fault find the build.

I got to testing it further on the weekend and it turns out I used the wrong 3.3v regulator on the board. The regulator pinout was incorrect which was why the RAM chip got hot. Once we fixed the regulator and mounted it in my H4 the computer showed a white screen only so this board may have damaged chips due to the regulator. I am planning to build another 2 boards with the correct regulator but this may not be until next weekend.

So still unsure if the XILINX chips are working or not.