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LT6502b progress
A lot has happened with LT6502b since my last post. Firstly the WiFi modem is now working, I finished the UART in a CPLD and it works a treat 🙂Secondly it’s now running at 10MHz, I can’t seem to get much above that, yet.Thirdly I’ve now added the nanoSwinSID chip onto the PCB and fitted the remaining keys. There are still a couple of things to sort; But I’m very happy with the progress. In regards the ModWires, one of these is no longer needed and the other was needed to signal to the CPLD when data is waiting to be sent from the KeyController/WiFi Modem, I’ve updated the Schematics…
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LT6502b
As much as I love my 6502 laptop, it felt a bit “chunky” at nearly 75mm deep and I really wanted a bigger screen as 9″ is a bit teeny. So I set about improving on that and the LT6502b project is underway, The main differences are; Things had been going very well; Compact flash working, console working, beeper working, 6522 VIA working and display working! Here is a 1024 x 600 Mandelbrot with 32 iterations, looks fabulous. Getting the screen working took the longest time, the new driver chip (RA8889) is way more complex than the previous RA8875 one, but was needed for the higher resolution/larger screen. That probably…
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LT6502 is assembled
I give you the very chonky 6502 based laptop; It has been quite the challenge to get this up and running, the main challenges code wise were;1) Getting the screen to work, and getting scrolling to work (that was way more effort than I thought it would be).2) Understanding EhBASIC and how it works so that I could add in extra commands. Talking of which here are the commands I’ve added; The biggest challenge of all for me was the case, what you is the 3rd or 4th revision of most parts. The hinges in particular were incredibly difficult.The hinges were inspired by this print – https://www.printables.com/model/658393-friction-hinge-mechanism/comments#preview.file.aPNjd. It took a…
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LT6502
Building on the PC6502 system I decided to make a laptop 6502 system. I think there’s something nice about having a portable retro system that is fully self contained. It’s going very well so far. It’s been quite a steep learning curve. I’ve been remembering the 6502 assembly coding I did back in the 1980s, slowly remembering. It’s been fun to bring the system up one bit at a time, starting EhBASIC, getting teh display working, the beeper and compact flash. So here is where I’m at; Here was the test of the comms with the keyboard, a simple “HELLO” from basic, which is being controlled by the console port…
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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.…