"Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?

Arc/RPCs, peripherals, RISCOS operating system & ARM kit eg GP2x, BeagleBoard
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IanS
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Re: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?

Post by IanS » Sat Sep 07, 2019 9:48 pm

steve3000 wrote:
Sat Sep 07, 2019 9:28 pm
Clearly Acorn changed the ROM wiring between the A310 and A3000, will the board work with the standard RO3 ROM carrier board in the A310, as this connected up the higher address lines?
The V1 ArcFlash fitted in my A310 fine, it effectively has the carrier board integrated, you feed the upper address lines directly onto the ArcFlash board. No need for the carrier board (though I guess it could be configured to work with one, if you didn't want to take a fitted carrier board out)

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myelin
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Re: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?

Post by myelin » Mon Sep 09, 2019 9:55 pm

Yes; Arcflash is designed so that /OE and the four high order address lines can be jumpered differently or attached to flying leads, so it's pretty flexible. I believe an A310 with a carrier board will look like an A3000 with its jumpers set up for 4Mbit JEDEC ROMs, so you would just set the jumpers on the Arcflash board to use the

In detail, the jumpers are:

/OE can be connected to GND or pin 24
A21 can be a flying lead or pin 1
A20 can be a flying lead or pin 31
A19 can be a flying lead or pin 30
A18 can be a flying lead or pin 2

The easiest way to hook into an unexpanded A310 is to jumper /OE to GND and use flying leads for A18-A21. An A3000 or an A4xx/1 can use a flying lead for A21 and jumpers for A18-20. An A540, or an A5000 or RISC PC with an adapter board, can use jumpers for everything.
Last edited by myelin on Mon Sep 09, 2019 9:55 pm, edited 1 time in total.
SW/EE from New Zealand, now in Mountain View, CA, making BBC/Electron hardware projects for fun.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.

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myelin
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Re: "Arcflash" A3000/A3xx/A4xx/A5xx/A5000 in-system programmable ROM -- any interest?

Post by myelin » Sat Sep 14, 2019 3:37 pm

Reset and POR both work! Verified in my A310 at least. Now I can double tap on reset to jump back to the bootloader, and selecting an OS triggers a power on reset too, so you can clear the NVRAM (necessary when switching between OS versions with incompatible NVRAM layouts).

This is all pushed to GitHub (firmware folder).
SW/EE from New Zealand, now in Mountain View, CA, making BBC/Electron hardware projects for fun.
Most interesting: Arcflash, FX2+PiTubeDirect Tube/Cartridge adapter, USB cart interface.

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