Acorn Electron part 1 (ULA)
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- Опубліковано 14 жов 2024
- In this video I take a look at the Acorn Electron, and more specifically the ULA. It's the heart of the system and creates one major difference from the BBC machines the Electron is derived from.
Stardot - stardot.org.uk
ULA schematic thread - [Electron ULA Schematics - stardot.org.uk](stardot.org.uk...)
FPGA ULA project - [Electron FPGA - stardot.org.uk](stardot.org.uk...)
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Hia, nice video. The Issue 1 board is a later German Issue 1, which actually came out after the "English" Issue 2 and probably same time as the Issue 6 boards, which is why it uses the same 'blob' style Malaysia ULAs.
I eventually got the Slogger accelerator board where you have a switch which is basically a 'Turbo' switch.
Out of curiosity I tried the same 3 line BASIC benchmark on an Electron emulator, and got exactly the same results. It was much slower in the higher graphics modes that use more RAM.
This is cool - I remember it well. The first Electron I had needed to go back after a week i think the keyboard had an issue. I liked the tactile and texture of the plastic. I was really chuffed to have my own computer when I was 9.
Also I seem to remeber there were 2 different keyboard / key types.
I spent way more hours than I'd care to admit on the little Electron - wrote a lot of code on it that was really targeted at the BBC B & Master Compact, including some ROMs. I still maintain that the BBC model A/B and those derived from them have the BEST BASIC of any microcomputer I've ever used! ...and with an assembler built in no less!
The power input jack goes more or less straight into a bridge rectifier to provide DC to everything else. Because of this the electron will also work from a DC supply. I use a 12V DC supply with mine, to save needing a UK plug adapter.
May be of interest: On my channel I have put in the community posts some pictures of my Electrons. One has the turbo board but that is crashing at the moment so I think it probably needs cleaning and re-seating of the pins.
Nice photos :-) I only have the one Electron myself, but I do have a couple of model B's, a couple of Master Compacts, and a Master 128 that's very sick!
Cost saving measure I suppose?
I'm working on a 68k project at the moment where I'm going to do something similar where in a single bus cycle I'll enable words (16 bits) to be read from a single ROM (8 bits), rather than needing an upper/lower ROM pair.
I'm using a CPLD which I guess is much like the ULA in the Acorn - although due to a lack of pins my latch and buffer are external.
Sounds like an interesting project :-) ...and yeah, 100% cost saving.
@@tassiebob Have nearly completed the schematic. Im hoping to fit it onto a 100x160 card so I can plug it into a subrack that ive got (VMEbus backplane), but Im a little worried Ive got too much circuitry on it. It'll have a couple of UARTs (single chip), 4MB of DRAM, plus timers and a couple of other bits and pieces, and an ethernet controller for fun. Its either going to be an extremely tight fit, or a double sided load, or maybe a 6 layer PCB, some combination of those, or it just wont fit. Will find out soon once Ive figured out the last little bits of the schematic... 😬
To get 32K of RAM the BBC Micro had used 16 x 16Kbit ICs. 32Kbit ICs were never a thing. By the time the Electron was made they could get 64Kbit ICs, so with the double accesses they could get away with only using four of them, to get the same 32K of RAM. It was quite a severe compromise though! In contrast in the "B+" they used the same 64Kbit ICs, but 8 of them instead of just four, and they used the upper 32K of memory for new purposes.
wow
Hello, can u private message me i need help with my keyboard that the Spacebar doesnt work properly keyboard is Logitech G412 carbon