Friday 14 October 2016

Acorn Electron RISC OS Pico

This is an Acorn Electron, but not any Acorn Electron. You might notice the cable coming out of the back, that's HDMI.
It boots up with a beep (a BBC style double beep) and within a few seconds, you get this mode 7 boot screen.
As you can see, it's got a touch more than the original 32K, about 6000 times more. The processor is also a lot faster (700MHz vs 1MHz).
OK, it's got a Raspberry Pi model A+ inside, but that's a RISC based chip, derived from the Acorn family, so it counts, doesn't it. The original power supply and keyboard are used, with a USB hub and one of my Acorn Electron USB keyboard controllers. More info on the original conversion of this Electron on the previous post, Acorn Electron with Raspberry Pi.
The Pi is now loaded with RISC OS Pico, a cut down version of RISC OS specifically for programming. It is running BBC BASIC, so you can just type in good old BASIC programs.
You can download the files and copy to a microSD card, or buy a version from them, I always try to support open source projects, so I got one of the official ones.
These now run quite a bit faster, so it is flying around the screen. On an original Electron, you can see the pause between printing each phrase, and then scrolling the page up, here you can't see it scrolling any more.
This is a more powerful version of BASIC which adds some new features, including more modes.
I'll zoom into the bottom corner of the screen, yes that's full HD mode.
The graphics can also make use of the full screen resolution.
You can also use the editor to create your BASIC programs.
The normal file access commands work to access files on the SD card, directly from the FAT32 folders rather than a separate partition or filing system as the Pi normally has. You can use *SCSI to change to reading a USB memory stick and *SDFS to change back to the microSD card.
The Electron keyboard is well suited to this as all the usual symbols are there, as well as the arrow keys and copy key etc., all working as the original. As with the Electron, shift + key gives the left hand symbol, ctrl+key gives the right hand. The function keys use function + number keys, with FUNC+0 for F10, FUNC+ -/= for F11 and FUNC+Break for F12.
The Electron had a unique feature in the Acorn range of having keywords printed on the keys, so originally, you could just press FUNC + C and COLOUR would appear on the screen as if you had typed it.
There is no support for that in RISC OS Pico, so I have added it to the USB keyboard controller. If you press FUNC+F, it will send the keys F, then O, then R, so FOR will appear on the screen. These are on all the letter keys, and some of the symbols. I've also added two more to the unused keys, FUNC with ;/+ now gives EDIT and return, to start the editor, and FUNC with :/* give *. and return to give a file listing. These keywords always need to be in upper case, so if caps lock is off, it holds down shift whilst typing the letters.

If you want to try this yourself, you can buy a suitably programmed USB keyboard controller kit, or contact me if you are interested in a complete Acorn Electron Pi preloaded with RISC OS Pico.

My thanks to John Dale who introduced me to RISC OS Pico and suggested pairing it with the Acorn Electron USB keyboard.

2023 Update

USB Keyboard Controller Kits are available from my Sell My Retro store: