Bygonebytes

More To Do's


While my workshop and Acorn computers are not available to use I still have the odd idea for what to do next. For instance I bought an Electron keyboard to fit into my Electron Clone.




I am thinking about adding some additional functionality to the clone Electron so I picked up a spare PSU and ULA socket/heatsink in preparation for building a new board.





Next up was an AP5 from Retro Hardware. This add-on has an I2C interface so I thought I'd get a small I2C display and a couple of temperature sensors to play with.







When I was looking at the small I2C displays I came across this 192x64 pixel 8 bit parallel graphic display. Something to plug into the dual User Ports.





Back in January 2022 I decided to build an Electron clone and at that time I chose to keep the design with standard 74 series logic and not go down the route of CPLD's or PAL. This made it easier to prove if I'd done some wrong..which it did! Now I'm thinking it's about time I delved into CPLD's and to see if I can reduce the chip count on the clone, currently sitting at 59.

I already have the tools to program the Xilinx XC95xx series of CPLD's as I used them on my Electron refurbishment project when building the Open Source Turbo card (OSTC) and the Minus One so it seems sensible to use them again. As I've never written any programs for these devices I thought I should have some practice so I bought a development board to try out some basic logic first. If successful I could then use the development board to replace some of the 74 series logic on one of my prototype clone PCB's. Not to get too far ahead of myself but I would then try to replace and reduce as much 74 series IC's as possible and build a v1.3 of the clone.

This is the development board I will be starting with:





I recently watched a youtube video from Adrian's Digital Basement where Adrian replaced the BBC Master battery and RTC chip with a small all-in-one module. As my Master is in storage with it's battery still connected I'm thinking it would be a good idea to replace it as soon as I get it back out.





Another Real Time Clock (RTC). This time I saw a Micro User RTC (from the February 1984 magazine) advertised on Ebay and thought I'd like to have a play with it and see if I could get it to work on my Electron. At 48 it is way too expensive to buy so I looked up the Micro User article and thought I could build it for a lot less so I designed a slightly modified version of the circuit and PCB.






I'll probably think of a few more projects in the coming months...