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PC6502 + Transputer
So, yeah, I have a thing for transputers, don’t ask me why, I don’t know. I’ve always been fascinated…. Anyway, I finally managed to get some reliable and repeatable comms between my 6502 tower and a T425 TRAM. Here you can see the data going out, and coming back in! In this case writing 0xEFBEADDE to address 0x80000000 (T425 internal RAM). Now this was supposed to be 0xDEADBEEF, but of course, the transputer is little endian.Anyway, output from BASIC program is below; I’ve tried this with the 4 TRAMs (Transputer Modules) I have and they all work!.Here is the tower with the link adapter and a single TRAM on top.…
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PC6502 update
I have been tinkering with various bits of the PC6502 computer system in between looking after Suzi (who is getting better slowly, but we still have a couple of months of hard work ahead of us). Previously I was able to show the OPL3 Sound and Speech card working, Here is an updated video of it playing a tune 🙂 Next I managed to get the display working, this is a 480×272 screen, it has built in fonts and a bunch of features line circle, line drawing and filling, so I can do a bunch of cool things as I go forward with it. I’ve not figured out how to…
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Hitting pause
Just after my last post our beloved Suzi Saluqi tore a ligament in her leg, she was in a lot of pain (she never makes a sound but oh boy she did this time), we took her straight to an emergency vet, got her something to help with the pain, next day we went to a vets to have it looked at and yes she needed surgery, a week later she had surgery. This was very traumatic for her, and also us, this was the first night she would be away from us in over 3 years. Suzi has been very good and is recovering well, she’s now able to…
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A synth project
Having had a couple of months break from synths I decided to pick up an old project (early 2025) and start work on it. This is user interface for the rather excellent XVA1 (or XFM2) from Futur3 Sounds so there is nothing of mine sound engine wise in there, so this is a step to getting back into making my own synths. We have a 480×272 TFT with touch screen, 11 OLED displays, 6 rotary encoders, 16 buttons (with LEDs) and a pot for volume (not fitted above). The touch screen is working as are all the OLEDs and buttons. Also the rotary encoders are working. On the back is…
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PC6502 Progress
In my previous blog entry I posted about the 6502 computer PCB I made, since then a lot of progress has been made. A lot. Firstly the timing issue has been overcome, the 6502 will now happily run at 14MHz (tested up to 17MHz), the issue was that the way I had implemented the logic in the CPLD for the FT245 serial port was messed up. My partner, Jayne, helped with that and found the issue. I’ve also added a whole bunch of different PCBs, so here’s a couple of pictures; So bottom to top; Aside from the Apple II slot everything is working a treat. Here is a demo…
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A win, sort of, but I’ll take it
Well the PCBs arrived and I decided to build up the CPU one slowly, not building the full thing. I’m glad I didn’t. Eventually after a lot of messing around with CPLD and ROM code I got something booting, it’s the Grant Searle ROM, but it worked. The sticking point seems to be serial comms. After much digging I discovered that the data on the data bus isn’t valid until 25nS after the clock edge, not a problem for older chips, but for the FT245 I’m using for the serial port it’s a problem. So after delaying the clock for the write a little I got some progress. So there…
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It’s been a month, or two
It’s been a while since I wrote, a lot has been going on. Firstly, the Transputer saga, I got a PCB from Oscar Toledo (https://github.com/nanochess/transputer) and confirmed that my TRAMs did indeed pass the tests with his card. However they did not with mine. Then I discovered that somehow none of my TRAMs worked with Oscar’s or my card. Very disheartening. So I’ve paused that for a while, there’s only so much failure you can take before you have to stop something for a bit. In the world of synths it seems things are slowing down globally, in part due to an orange womble in the USA. I have to…
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Finally, data (Fun with Transputers)
I finally managed to get data into and out of the transputer module (TRAM). To do this I used an Arduino Micro I had (as it’s 5V) and some breadboard. Now the TRAM pulls 800mA at 5V and the breadboard struggles with this, so I ended up using 4 links for 0V and 4 links for 5V and pushing the power supply to 5.5V to get 5V on the TRAM (not a problem on a PCB). I added some LEDs to various signals just so I had some confirmation that it was actually doing something.I also ran the transputer links at 10Mbps rather than 20 as I was concerned about…
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Retro computing and projects
I have, as many of you probably know, a bit of a thing for retro computing. This doesn’t help with my ongoing stack of projects. But it is what it is. Lately I’ve dived deep into the world of Transputers. I also have a PC104 form factor PC (Celeron).Now I kinda like the PC104 form factor, it’s cute and PCBs are cheap (being under 100mm by 100mm), but it’s not without it’s challenges. The Transputer connects to a host via a Link controller (C012 or C011), this turns 8 bit data into 32bit streams which in turn gets passed to the first Transputer. The Transputer Module (called a TRAM) is…
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Time for a change, just for a while
These days my day-job keeps me very busy, I enjoy what I do but it does mean I have very little energy left by the end of the week. With that in mind, I’ve made a decision; I will be pausing synth development (other than Quadrowave for Isla Instruments) for a while, I don’t know how long that will be. I need a change. I’ve been playing with some old computer tech, including the PJ5 CPU project. I’ve got an old PC104plus style PC up and working (Celeron M) and I can play some games on it (Doom, Monkey Island, etc). It currently has no soundcard (well it has an…