64K to 128K upgrade

discuss both original and modern hardware for the bbc micro/electron
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Sniffer
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Re: 64K to 128K upgrade

Post by Sniffer » Tue May 07, 2019 8:27 pm

I thought L13 meant S13, don't know why!
Now I know why I thought that. The post refers to L9, L11, L12, L15 or L18 but actualy means S9, S11, S12, S15 or S18, along the east of the board.

So, is there an actual L13? I now think it does mean $13 which brings me back to my original question. Both pin 20s can't be connected to the same point can they?

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DutchAcorn
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Re: 64K to 128K upgrade

Post by DutchAcorn » Tue May 07, 2019 9:25 pm

Sniffer wrote:
Tue May 07, 2019 8:27 pm
I thought L13 meant S13, don't know why!
Now I know why I thought that. The post refers to L9, L11, L12, L15 or L18 but actualy means S9, S11, S12, S15 or S18, along the east of the board.

So, is there an actual L13? I now think it does mean $13 which brings me back to my original question. Both pin 20s can't be connected to the same point can they?
Oops, I opened up my B+ to check what I had done. One of the pin 20s is connected to the NORTH pin of S13, the other to the south pin. The description mentions that you should use the “unused pin of S13”. In my case that was the north pin of S13. Sorry for the confusion.

No, they can’t be connected to the same point.
Paul

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Sniffer
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Re: 64K to 128K upgrade

Post by Sniffer » Tue May 07, 2019 9:33 pm

Sorry for the confusion.
Absolutely no problem, thanks for taking the time to check.

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Sniffer
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Re: 64K to 128K upgrade

Post by Sniffer » Thu May 09, 2019 8:19 am

For a full RAM count you want RAMCount.
How is this used? I can see it's not basic.

Remklep
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Re: 64K to 128K upgrade

Post by Remklep » Sat Jan 04, 2020 12:38 pm

Gents,

I just did the 64-128kB upgrade to my model B+ and have some questions.
The first time I started the B+ it said:
Acorn OS 128K
Acorn 1770 DFS
BASIC

So everything was as expected.

But when I press Break it says:
Acorn OS
Acorn 1770 DFS
BASIC

Other times I have seen it display 96K or 112K.

I'm assuming this is not normal?

Thnx
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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1024MAK
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Re: 64K to 128K upgrade

Post by 1024MAK » Sat Jan 04, 2020 12:41 pm

Not giving the size after just pressing BREAK is normal.

After power up, the size should however be consistent.

Mark

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Re: 64K to 128K upgrade

Post by Remklep » Sat Jan 04, 2020 12:52 pm

Hi 1024MAK,

Thnx for the info.
When I switch off the model B+ and switch it back on after a second or 2 it reports 96K.
If, however, I switch it off and press a keyboard button, it reports 128K again after power on.
I guess it's a capacitor thats still charged, getting discharged by pressing a button.
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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Re: 64K to 128K upgrade

Post by Remklep » Sat Jan 04, 2020 12:54 pm

I ran the 410 line memtest program and this was the output...
IMG_5692.JPG
Seems to me there should be some RAM locations, or not?
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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1024MAK
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Re: 64K to 128K upgrade

Post by 1024MAK » Sat Jan 04, 2020 12:58 pm

There is another thread about upgrading a B+, this post gives details on how the machine decides how much RAM it has.

Mark

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Re: 64K to 128K upgrade

Post by marcusjambler » Sat Jan 04, 2020 1:00 pm

I have a B+ that does this
I found that if I move the ROMS ( not OS ) around it changes the reported RAM :shock:

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Re: 64K to 128K upgrade

Post by rmbrowngr » Sat Jan 04, 2020 1:05 pm

I've done this upgrade and have the following arrangement of ROMs and RAM:-

DFS version 2.26 (if you don't have it I wopiuld recommend you get it) IC62
BASIC and OS IC71
Sideways RAM IC57

And I always get 128k on power on and crtl+break
Richard B
Acorn Electrons issue 4 and 6, MRB, Plus 1, AP6, AP5, Pegasus 400, BeebSCSI, Gotek, Raspberry Pi, GoSDC MBE.
BBC B+ 64K (128K upgraded) with Duel OS, Raspberry Pi and Gotek.

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Re: 64K to 128K upgrade

Post by rmbrowngr » Sat Jan 04, 2020 1:07 pm

Remklep wrote:
Sat Jan 04, 2020 12:54 pm
I ran the 410 line memtest program and this was the output...

IMG_5692.JPG

Seems to me there should be some RAM locations, or not?
This doesn't look right to me e.g. no RAM reported. Once you get RAM listed the next test is to load something into sideways RAM.

And this might be useful to read viewtopic.php?f=3&t=16789. Contains my experience on performing this upgrade. You can always use a version of Elite that using SWRAM once the get the upgrade working.

Also, there a some other tools for SWRAM available on mdfs.net http://mdfs.net/Software/BBC/SROM/
Richard B
Acorn Electrons issue 4 and 6, MRB, Plus 1, AP6, AP5, Pegasus 400, BeebSCSI, Gotek, Raspberry Pi, GoSDC MBE.
BBC B+ 64K (128K upgraded) with Duel OS, Raspberry Pi and Gotek.

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Re: 64K to 128K upgrade

Post by Remklep » Sat Jan 04, 2020 1:39 pm

Mea Culpa!... #-o

What a big difference a ":" in stead of a "*" makes in a little 410 line program... :oops:

After running the corrected program:
IMG_5693.JPG
But when running it a second time:
IMG_5694.JPG
So something IS going on.
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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Re: 64K to 128K upgrade

Post by rmbrowngr » Sat Jan 04, 2020 1:43 pm

Connect the other extra pin 20 to the spare pin of L13 (CS for either roms 0/1 or 14/15, depending on where you want BASIC)
Richard B
Acorn Electrons issue 4 and 6, MRB, Plus 1, AP6, AP5, Pegasus 400, BeebSCSI, Gotek, Raspberry Pi, GoSDC MBE.
BBC B+ 64K (128K upgraded) with Duel OS, Raspberry Pi and Gotek.

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Re: 64K to 128K upgrade

Post by Remklep » Sat Jan 04, 2020 1:59 pm

rmbrowngr wrote:
Sat Jan 04, 2020 1:43 pm
Connect the other extra pin 20 to the spare pin of L13 (CS for either roms 0/1 or 14/15, depending on where you want BASIC)
I have.
One pin 20 goes to pin9 of IC46, the other pin20 goes to the unused north pin of S13.
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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Re: 64K to 128K upgrade

Post by Remklep » Sat Jan 04, 2020 2:02 pm

After putting jumper L12 in the East position (rest of L jumpers in in the West position) the RomRam test is now consistent and shows RAM in 6,7,12 and 13.
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

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1024MAK
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Re: 64K to 128K upgrade

Post by 1024MAK » Sat Jan 04, 2020 3:30 pm

See also this thread.

Mark

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Re: 64K to 128K upgrade

Post by rmbrowngr » Sat Jan 04, 2020 5:17 pm

A picture guide to how I have the SWRAM setup:

ROMS
IMG_3278.jpg
IMG_3278.jpg (18 KiB) Viewed 377 times
RAM\ROM List Disk attached below the pictures
IMG_3279.jpg
Top View
IMG_3280.jpg
Side view 1
IMG_3281.jpg
side view 2
IMG_3282.jpg
Disk image (DFS) for B+ with the ROM\RAM list program saved as "RTEST".
bplus.zip
(12.12 KiB) Downloaded 5 times
64K SIDEWAYS RAM DAUGHTER BOARD FITTING INSTRUCTIONS, if you're interested
BBCB+64k.zip
(2.96 KiB) Downloaded 6 times
BBC Microcomputer model B+ with 128K RAM, Additional User Information
BPlus128KAdditionalUserInfo.zip
(22.57 KiB) Downloaded 4 times
Richard B
Acorn Electrons issue 4 and 6, MRB, Plus 1, AP6, AP5, Pegasus 400, BeebSCSI, Gotek, Raspberry Pi, GoSDC MBE.
BBC B+ 64K (128K upgraded) with Duel OS, Raspberry Pi and Gotek.

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Re: 64K to 128K upgrade

Post by Remklep » Mon Jan 20, 2020 9:38 pm

Finally took some time to look at my stack of chips.
Turned out some legs weren't soldered together properly.
Mea Culpa...

It works perfect now.
BBC Model B+ 64K, 128K Memory Mod, RetroClinic External PiDirect with Raspberry Pi 3B.
BBC Master 128, RetroClinic Internal PiDirect with Raspberry Zero, TurboSPI MMC, RobC's VideoNuLa, Gotek Floppy Emulator.

Kazzie
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Re: 64K to 128K upgrade

Post by Kazzie » Tue Jan 21, 2020 5:26 am

Remklep wrote:
Mon Jan 20, 2020 9:38 pm
Finally took some time to look at my stack of chips.
Turned out some legs weren't soldered together properly.
Mea Culpa...

It works perfect now.
Well done! =D>

We've all done something similar at some point. (Here's one of my finest... #-o )
BBC Model B 32k issue 7, Sidewise ROM board with 16K RAM
Archimedes 420/1 upgraded to 4MB RAM, ZIDEFS with 512MB CF card
Acorn System 1 home-made replica

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