Burning MOS on M27C256B

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KarateEd
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Burning MOS on M27C256B

Post by KarateEd » Tue Jul 30, 2019 4:57 am

Hi Folks,

I want to burn MOS 5 (for Master Compact to go into an Ollivetti) onto an M27C256B EEPROM.

My question is will it work and what part of the chip will I need to put the ROM image on?

I am using a MiniPro burner. Model TL866CS if any of that is helpful.

Thanks very much, I'm hoping to do this tomorrow for a friend.
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

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1024MAK
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Re: Burning MOS on M27C256B

Post by 1024MAK » Tue Jul 30, 2019 8:28 am

I think the Master Compact uses a 64K byte mask ROM chip. So you would need a 27512 (or 27C512) EPROM.

Mark

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KarateEd
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Re: Burning MOS on M27C256B

Post by KarateEd » Tue Jul 30, 2019 9:06 am

1024MAK wrote:
Tue Jul 30, 2019 8:28 am
I think the Master Compact uses a 64K byte mask ROM chip. So you would need a 27512 (or 27C512) EPROM.

Mark
Well, that's curious because I tried to burn a ROM image I got offline of ver. 5.1 and it doesn't even take up 1/2 the ROM.

Why do you think that is?

Thanks Mark,
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

johnkenyon
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Re: Burning MOS on M27C256B

Post by johnkenyon » Tue Jul 30, 2019 9:31 am

The images at http://mdfs.net/System/ROMs/AcornMOS/Compact510/ and http://mdfs.net/System/ROMs/AcornMOS/Compact511/
are both 65536 bytes in size.

Bear in mind that the 64K ROM contains ADFS, Basic, Utils, plus MOS.
Are you sure you haven't just got the MOS bit?
Last edited by johnkenyon on Tue Jul 30, 2019 9:34 am, edited 1 time in total.

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jgharston
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Re: Burning MOS on M27C256B

Post by jgharston » Tue Jul 30, 2019 9:47 am

The MOS5 64K ROM is laid out as:
0000: MOS (&C000)
4000: ROM 13 (ADFS)
8000: ROM 14 (BASIC)
C000: ROM 15 (UTILS)

Code: Select all

$ bbcbasic
PDP11 BBC BASIC IV Version 0.32
(C) Copyright J.G.Harston 1989,2005-2020
>_

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KarateEd
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Re: Burning MOS on M27C256B

Post by KarateEd » Tue Jul 30, 2019 4:28 pm

Ok, thanks guys. There is obviously more to this than meets the eye.....

I will have to get some larger EEPROMS.
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

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Re: Burning MOS on M27C256B

Post by KarateEd » Tue Jul 30, 2019 4:33 pm

Is it possible to burn just a portion of the main chip with only some of the items and then put the rest on another chip?

That way we may be able to have everything but just in a slightly different configuration.
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

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Re: Burning MOS on M27C256B

Post by KarateEd » Tue Jul 30, 2019 4:36 pm

One more question, sorry they keep popping into my head.

How would I go about burning each ROM into one chip. Can you do several burns just using the different locations?
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

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Re: Burning MOS on M27C256B

Post by 1024MAK » Tue Jul 30, 2019 8:23 pm

KarateEd wrote:
Tue Jul 30, 2019 4:33 pm
Is it possible to burn just a portion of the main chip with only some of the items and then put the rest on another chip?

That way we may be able to have everything but just in a slightly different configuration.
Is it possible, yes. One possible solution would be to piggyback two EPROM chips. But given that 27C512 EPROM chips should still be available, that is the preferred option.
KarateEd wrote:
Tue Jul 30, 2019 4:36 pm
One more question, sorry they keep popping into my head.

How would I go about burning each ROM into one chip. Can you do several burns just using the different locations?
If the file length of each file is an exact multiple of 16384, then you can use a suitable utility program or for some PC OSs, the OS file system can join files together.
Some EPROM/EEPROM programmer software can also do this.

Yes, most EPROM/EEPROM programmers will allow you to either assemble a ROM file in RAM, then ‘burn’ this copy in RAM to the EPROM/EEPROM. And / or allow you to select a start address (and either a length or an end address) in the EPROM/EEPROM when ‘burning’. Note that the start / end addresses are the addresses as seen by the programmer when accessing the EPROM/EEPROM, NOT CPU addresses.

Mark

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Re: Burning MOS on M27C256B

Post by KarateEd » Tue Jul 30, 2019 9:39 pm

Thanks Mark...... I've done a couple burns, we'll see what happens when my friend gets here and we put the chips in.
Ed...... :-)

3 working Beebs, 1 RetroClinic Master, 1 normal Master, 1 A3010, 1 Pi2 RISC OS, 2 broken Beeb Motherboards, 1 Omnibus A7000+ server, 1 A7000+ Desktop, 1 PET, 1 C64, 1 C128, 1 Amiga 500 and 1 Roamer.

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