USA spec BBC model B

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Lardo Boffin
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USA spec BBC model B

Post by Lardo Boffin » Tue Jul 31, 2018 6:54 am

Does anyone know which, if any, add ons will work with USA spec beebs?
I assume disc drives and anything else that connects via the standard ports will work but what about sideways RAM / ROM or even EEPROM? I believe they have 32K ROM sockets (i.e. 2 * 16K banks per socket) so will be boopib memory work?
Obviously normal sideways RAM boards won’t due to the different layout ignoring any electrical differences.

Any help appreciated as ever!
Atom, issue 5
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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Re: USA spec BBC model B

Post by steve3000 » Tue Jul 31, 2018 8:28 am

Yes they have 32kb ROM sockets. But I've not tired sideways RAM in my US beeb, mainly because it's stopped working :(

I suspect it would be possible to get working, but the location any flying leads pick up signals from would be different - although this shouldn't be difficult to work out for sideways RAM especially if it picks up signals from ICs (most of which are the same, just with different numbering and location).

Without a circuit diagram it's going to be difficult to know for sure unless you try. Until mine stopped working, I'd been working on the assumption the US beeb is part-way between an issue 7 beeb and a B+...

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Re: USA spec BBC model B

Post by cmorley » Tue Jul 31, 2018 9:22 am

Lardo Boffin wrote:
Tue Jul 31, 2018 6:54 am
I assume disc drives and anything else that connects via the standard ports will work but what about sideways RAM / ROM or even EEPROM? I believe they have 32K ROM sockets (i.e. 2 * 16K banks per socket) so will be boopib memory work?
I don't know anything about the US spec Beeb but if it has 32K sockets and isn't electrically the same as a B in the sideways ROM socket department then my B upgrades won't work.

If it does have 32K sockets then you can drop in a 62256 and a flylead to NWDS (with pull up and write protect switch if desired) for a few £ very easily.

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Re: USA spec BBC model B

Post by Lardo Boffin » Tue Jul 31, 2018 10:34 am

cmorley wrote:
Tue Jul 31, 2018 9:22 am
Lardo Boffin wrote:
Tue Jul 31, 2018 6:54 am
I assume disc drives and anything else that connects via the standard ports will work but what about sideways RAM / ROM or even EEPROM? I believe they have 32K ROM sockets (i.e. 2 * 16K banks per socket) so will be boopib memory work?
I don't know anything about the US spec Beeb but if it has 32K sockets and isn't electrically the same as a B in the sideways ROM socket department then my B upgrades won't work.

If it does have 32K sockets then you can drop in a 62256 and a flylead to NWDS (with pull up and write protect switch if desired) for a few £ very easily.
Thanks. Would this give standard sideways RAM such that Exile (for example) would be able to use it?
Atom, issue 5
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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Re: USA spec BBC model B

Post by cmorley » Tue Jul 31, 2018 10:37 am

Lardo Boffin wrote:
Tue Jul 31, 2018 10:34 am
Thanks. Would this give standard sideways RAM such that Exile (for example) would be able to use it?
Yes it should work fine with Exile.

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Re: USA spec BBC model B

Post by Lardo Boffin » Thu Aug 30, 2018 10:37 am

And here is the ANB09. Very nice condition and only ever briefly tested after assembly before I got it. As close as it is possible to get to a new beeb!

E364CA0A-B690-4102-8695-55F1473F3C2B.jpeg
Atom, issue 5
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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Re: USA spec BBC model B

Post by CMcDougall » Thu Aug 30, 2018 10:49 am

^ nice, but did they all have a ashtray cover on the left? :?
I like all mine to still have them unpushed out 8)
ImageImageImage

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Re: USA spec BBC model B

Post by Pernod » Thu Aug 30, 2018 10:57 am

CMcDougall wrote:
Thu Aug 30, 2018 10:49 am
^ nice, but did they all have a ashtray cover on the left? :?
Very likely as they had the US speech fitted as standard.
- Nigel

BBC Model B: ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, BeebZIF, etc.

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Re: USA spec BBC model B

Post by Lardo Boffin » Thu Aug 30, 2018 12:43 pm

Pernod wrote:
Thu Aug 30, 2018 10:57 am
CMcDougall wrote:
Thu Aug 30, 2018 10:49 am
^ nice, but did they all have a ashtray cover on the left? :?
Very likely as they had the US speech fitted as standard.
I believe that they all have them like that. Certainly all the images I have ever seen.
It has speech but I have not tested as I am not sure I will like the accent... :?
Atom, issue 5
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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Re: USA spec BBC model B

Post by AndyGarton » Thu Aug 30, 2018 2:07 pm

What a fantastic looking thing! Very jealous - I assume these come up for sale very rarely? If you know where I could get one in similar condition, please share :D

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Re: USA spec BBC model B

Post by Lardo Boffin » Thu Aug 30, 2018 3:47 pm

AndyGarton wrote:
Thu Aug 30, 2018 2:07 pm
What a fantastic looking thing! Very jealous - I assume these come up for sale very rarely? If you know where I could get one in similar condition, please share :D
To be honest the photo doesn’t do it justice.

There were three (I think) up for sale recently on eBay as kits at £300 each. I got mine elsewhere - I will ask if there are any more but I have no idea if this is the case. There was no mention of any more.
Atom, issue 5
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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Re: USA spec BBC model B

Post by AndyF » Thu Aug 30, 2018 5:41 pm

I was not aware Speech was fitted as standard, I did have a 'UK' 'B that had it at one point, gave it away actually to a member on another forum (said machine needed a few bits though) , I may be thinking of the German (?) machines, not sure.

I had assumed they all had Disc (and very likely Econet) fitted as standard though, guessing the later 177x series regarding disc rather than the older 8271 setup. Then again the 8271 means a single DNFS chip rather than either two chips or a combi of 177x DFS and NFS into one larger ROM. :oops:
Last edited by AndyF on Thu Aug 30, 2018 5:41 pm, edited 1 time in total.
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Re: USA spec BBC model B

Post by Lardo Boffin » Thu Aug 30, 2018 5:58 pm

I think they had to up their game for America. :D

I will open it later and post some photos of the inside.
Atom, issue 5
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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Re: USA spec BBC model B

Post by Pernod » Thu Aug 30, 2018 6:09 pm

AndyF wrote:
Thu Aug 30, 2018 5:41 pm
I had assumed they all had Disc (and very likely Econet) fitted as standard though, guessing the later 177x series regarding disc rather than the older 8271 setup. Then again the 8271 means a single DNFS chip rather than either two chips or a combi of 177x DFS and NFS into one larger ROM. :oops:
Standard 8271 FDC but used DNFS 1.0 rather than the more common 1.2. The OS and BASIC were unique too, being slightly modified for US NTSC screen sizes and keywords COLOUR->COLOR. Also contained VIEW as standard.
- Nigel

BBC Model B: ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, BeebZIF, etc.

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Re: USA spec BBC model B

Post by AndyF » Thu Aug 30, 2018 7:23 pm

Lardo Boffin wrote:
Thu Aug 30, 2018 5:58 pm
I think they had to up their game for America. :D

I will open it later and post some photos of the inside.
Would be good to see. I did actually check Ian's site to see if he had any US 'Spec models and found this...

https://www.beebmaster.co.uk/USBBCB.html

EDIT...

... and this ...

http://www.beebmaster.co.uk/BM10/USBeeb.html

... so it would be interesting to see if/what/how yours differs internally. :)
Pernod wrote:
Thu Aug 30, 2018 6:09 pm
Standard 8271 FDC but used DNFS 1.0 rather than the more common 1.2. The OS and BASIC were unique too, being slightly modified for US NTSC screen sizes and keywords COLOUR->COLOR. Also contained VIEW as standard.
Thank you for the clarification Nigel. :) I was aware of COLOUR vs COLOR and likely a different modulator fitted but forgot to mention them in my original post.
Last edited by AndyF on Thu Aug 30, 2018 7:25 pm, edited 2 times in total.
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Re: USA spec BBC model B

Post by Lardo Boffin » Thu Aug 30, 2018 7:29 pm

Some Beeb p**n. Mine has been converted to UK so has different ROMs by the looks of it.

I can add any more as required. The shiny metal made it difficult to get decent photos with my phone.

CE280CC8-1D7F-441C-B9C6-68FD70C1AC6E.jpeg
564BDC5C-428D-4C25-BB53-A8BA93B89347.jpeg
FA6DB205-5007-423F-B4B7-EAF4DDE19D25.jpeg
5F1EF4B5-1454-4107-87CB-94E6F2686C93.jpeg
78B02B32-C7CF-49A6-B42E-6DAD38AB4A3A.jpeg
Atom, issue 5
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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Re: USA spec BBC model B

Post by tricky » Sat Sep 01, 2018 9:24 am

Have you tried any beeb software, particularly games that access the screen directly (all mine ;))?
Are there any Hz issues? I guess RF (NTSC) won't work, but what about composite or rgb if it has them.
I know Arcadian had a USA beeb, I wonder if he still has it.

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Re: USA spec BBC model B

Post by Lardo Boffin » Sat Sep 01, 2018 10:40 am

tricky wrote:
Sat Sep 01, 2018 9:24 am
Have you tried any beeb software, particularly games that access the screen directly (all mine ;))?
Are there any Hz issues? I guess RF (NTSC) won't work, but what about composite or rgb if it has them.
I know Arcadian had a USA beeb, I wonder if he still has it.
It has RGB out and works with the same SCART as my normal beeb. It runs Elite OK but thats all I have checked so far. I can’t find the ROM for my Turbo MMC and don’t have much else on disc. I will have to copy some stuff across. :D
Atom, issue 5
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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Re: USA spec BBC model B

Post by AndyF » Sat Sep 01, 2018 12:31 pm

Ian's results with the "Welcome!" software was quite interesting (link in my post above I think) although the differing resolutions did explain this.

I do suspect there was a 'Welcome' type pack for the machines 'across the pond' or if not that pack, something would of been bundled into the box, aside from any retailer added bonus aka a random game disc/tape or three. Ultimately you'd get something I'm sure, I cannot think of a machine of any make that did not get something at least thrown in.

Talking of which, seems you'd need NTSC / US specification games, so I am not sure either what 'intended' software was available.
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Re: USA spec BBC model B

Post by Pernod » Sat Sep 01, 2018 1:19 pm

AndyF wrote:
Sat Sep 01, 2018 12:31 pm
I do suspect there was a 'Welcome' type pack for the machines 'across the pond' or if not that pack, something would of been bundled into the box, aside from any retailer added bonus aka a random game disc/tape or three.
Yep, attached. Probably came from somewhere else on the forum but not easy to search for.
Attachments
introductory_utils(1983)(acorn).zip
(41.43 KiB) Downloaded 11 times
- Nigel

BBC Model B: ATPL Sidewise, Acorn Speech, 2xWatford Floppy Drives, AMX Mouse, Viglen case, BeebZIF, etc.

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Re: USA spec BBC model B

Post by steve3000 » Sat Sep 01, 2018 10:12 pm

Nice pictures :) but just a bit too dark to see all the links, any chance next time you have it open, you could take a photo of the whole PCB with all the links visible? I'm struggling to find anywhere with a picture of a US beeb PCB that clearly show the link settings...

My US beeb kind-of works but has lots of graphic issues, that may be related to a link set incorrectly, but I can find no documentation of the correct settings - and all links are numbered differently to the UK beeb :(

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Re: USA spec BBC model B

Post by AndyF » Sun Sep 02, 2018 5:40 pm

Pernod wrote:
Sat Sep 01, 2018 1:19 pm
AndyF wrote:
Sat Sep 01, 2018 12:31 pm
I do suspect there was a 'Welcome' type pack for the machines 'across the pond' or if not that pack, something would of been bundled into the box, aside from any retailer added bonus aka a random game disc/tape or three.
Yep, attached. Probably came from somewhere else on the forum but not easy to search for.
Thank you.

That does bear a passing resemblance to the Electron one :?: , as in a DFS version of their ADFS 'Welcome' , I think so its been ages since I saw the Elk one actually. Perhaps it was the green background playing tricks with me. :oops:

I can't compare them at the moment as the machine I'm using to type this reply has no emulators present, although I did look at said file late yesterday. Perhaps that is what they had. I do recall the pic being shifted a bit when looking at it on BeebEm although (it was late and I was half asleep!) I'm sure I saw something saying Electron in the very last program, I could be wrong. I need to reverify what I saw tomorrow. :)
Last edited by AndyF on Sun Sep 02, 2018 5:41 pm, edited 2 times in total.
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Re: USA spec BBC model B

Post by BeebMaster » Sun Sep 02, 2018 8:54 pm

It's funny because although my first Beeb all that time ago was a "US Beeb", and in 2013 I bought a "US Beeb" to celebrate 10 years online, in reality I have never owned a genuine US Beeb.

By "genuine US Beeb" I mean the US motherboard variety, with disc, speech and Econet interfaces, US version of BBC BASIC (sometimes called BASIC III), US OS outputting NTSC video, View ROM, Faraday cage over the motherboard, 120V PSU, and cartridge ROM socket fitted to the keyboard.

A Beeb of that spec is actually almost unheard of nowadays.

Most "US Beebs" seem to be those you used to read about in the adverts in Acorn User being machines returned to the UK from America and converted back for UK use with 240V PSU, UK OS 1.20 and BASIC II.

My 1991 Beeb was a real curiosity, although it was only years later that I realised. I wish I still had it, there are no pictures or screenshots from the time. The only record of it I have is my correspondence with Watford Electronics when I tried to upgrade to 1770 FDC and failed.

That Beeb was the US motherboard, but it had the German OS - the only one ever to report "Acorn OS 32K" on start up - with PAL output, 8271 DFS, and still the Faraday cage over the motherboard. I can't say whether it had speech or Econet. Documentation was hard to come by back then, so I don't think I would have known how the test/work the speech upgrade, and amazingly I had no use for Econet at that time, so I probably never tried *NET or N-BREAK. I'm about 99% certain it had BASIC II and PAGE at &1900 but again I can't recall. I don't think View was in there.

The 2013 one was the US motherboard, and said it had US OS but it was actually UK OS 1.20, no Faraday cage, but does have Econet and (US) speech as well as 8271 DFS and View.
Image

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Re: USA spec BBC model B

Post by flynnjs » Sun Sep 02, 2018 11:03 pm

AFAIK the US and German mobos are the same, it's only the OS and Language that differ.
The German OS only differs from a standard UK OS in the startup banner, other than
that they are byte identical.
I suspect many "US converted back to UK" beebs are actually just German ones.

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Re: USA spec BBC model B

Post by steve3000 » Mon Sep 03, 2018 7:00 am

flynnjs wrote:
Sun Sep 02, 2018 11:03 pm
I suspect many "US converted back to UK" beebs are actually just German ones.
Not sure this is correct, although the differences are small between these. US beeb PCBs were always fully populated and included the US speech chips, whereas German beebs were not typically sold fully populated and didn't have the US speech chips. Other differences are the font used on the function key strip, and text on the underneath and back of the computer which is different for US market and the US serial number.

I've got a technical document somewhere which describes the process to convert a US market beeb back to UK spec for UK resale, so this definitely happened.

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Re: USA spec BBC model B

Post by Lardo Boffin » Mon Sep 03, 2018 8:44 am

Mine was sold by a trustworthy seller as a USA kit that had been assembled and converted to UK spec so it must happen from time to time. :D
Atom, issue 5
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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Re: USA spec BBC model B

Post by BeebMaster » Mon Sep 03, 2018 8:53 pm

steve3000 wrote:
US beeb PCBs were always fully populated and included the US speech chips, whereas German beebs were not typically sold fully populated and didn't have the US speech chips. Other differences are the font used on the function key strip, and text on the underneath and back of the computer which is different for US market and the US serial number.

I've got a technical document somewhere which describes the process to convert a US market beeb back to UK spec for UK resale, so this definitely happened.
That tends to support my theory formed in 2013 that my original US Beeb was in fact a German one. Chris's Acorns shows a German Beeb with the Faraday cage, but the US convert to UK without.

It looks like in 2023 I will have to buy a German Beeb to really relive my original Beeb experience!
Image

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Re: USA spec BBC model B

Post by Lardo Boffin » Wed Sep 05, 2018 1:27 pm

steve3000 wrote:
Sat Sep 01, 2018 10:12 pm
Nice pictures :) but just a bit too dark to see all the links, any chance next time you have it open, you could take a photo of the whole PCB with all the links visible? I'm struggling to find anywhere with a picture of a US beeb PCB that clearly show the link settings...

My US beeb kind-of works but has lots of graphic issues, that may be related to a link set incorrectly, but I can find no documentation of the correct settings - and all links are numbered differently to the UK beeb :(
Photos below. Let me know if you need any specific links / images. I can email photos if required - the resolution is somewhat reduced by the forum I think.

0795A17E-5D7F-4FC6-A4AB-52E69C116341.jpeg
58EA76D9-356B-46D0-89BB-12187973C073.jpeg
0033F1F6-650E-42CD-AB69-294D4D6A83CF.jpeg
Atom, issue 5
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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Re: USA spec BBC model B

Post by Lardo Boffin » Wed Sep 05, 2018 1:29 pm

Does anyone know if you have to change / set links to put ROMs in the sockets? E.g. if you wish to put a 16k ROM in a socket as they are 32k sockets?

I will like to fit my SD card reader from sir morris but want to make sure I don’t kill anything!
Atom, issue 5
BBC model B 32k issue 4, 16k sideways RAM, Watford 12 ROM board, Acorn 6502 coproc
BBC model B 32k issue 7, turboMMC, Opus Challenger 3 512k, Pi 3 coproc
USA Model B
BBC Master, Datacentre + HDD, pi co-proc, econet, NULA

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Re: USA spec BBC model B

Post by 1024MAK » Wed Sep 05, 2018 2:56 pm

On the B+ Acorn provided 32K byte compatible EPROM/ROM sockets suitable for 2764, 27128 and 27256 EPROMs.

The only difference between a 16K byte 27128 and a 32K byte 27256 EPROM is pin 27. On a 27128 it is /PGM and should (normally) be held at +5V for normal operation. On a 27256 EPROM, pin 27 is address line A14. A14 effectively selects either the 'top half' or the 'bottom half' with each half being seen in different 'slots' (or banks).

So on the B+ Acorn provided a link for each socket to select between +5V or an address line signal "A14" (although due to the actual memory layout, this actually comes from the chip that provides the ROM latch functionality, not an address line from the CPU).

Here is a diagram showing the different pinouts of common EPROMs:-
Image

Not having a USA Beeb, and not knowing of any technical documentation, I can't say how Acorn configured the ROM sockets in this model. But I would expect it to be similar.

Mark

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