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68705P3 MCU

I have is my possession two 68705P3 MPUs. One has corrupted data in the EPROM portion and i need to re-program it (erasing it is easy as it has the usual 'window').

I have a modern EPROM programmer that doesn't appear to directly support this device.

I do though have on my PC a binary of the EPROM portion of the MCU.

Is there any way I can 'fool' my EPROM programmer into programming the EPROM side of the MCU?

The binary is only 2K in size so I would imagine that the EPROM part is a 2716 or equivalent?

Thanks

Reply to
rgb-man
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That should of course be MCUs. :)

Reply to
rgb-man

I think the answer is no, but there is a very simple schematic available somewhere that allow to connect a 68705P3 and an already programmed Eprom (2764 or so), and the 68705P3 program itself, reading the Eprom. I'm quite sure it was an application note from Motorola.

Robert Lacoste - ALCIOM : The mixed signals experts

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Reply to
Robert Lacoste

Interesting, thanks. I'll have a look around for the schematic you mentioned, but if anyone knows where to find it please let me know. :)

Cheers

Reply to
rgb-man

The programmer schematic should be in Motorola's 68705 family manuals

- don't know if those would still be available on Motorola's web site...

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Peter Bennett VE7CEI 
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Reply to
Peter Bennett

Thanks, have looked via a search on '68705' but no result.

Reply to
rgb-man

The MC68705P3 programs itself from a ROM or EPROM when both are inserted in a special programmer. As someone already mentioned, the schematic for the special programmer is in the Motorola databooks. The circuit is simple, doesn't require a lot of parts. Burning an EPROM in order to program the uC is a pain though. I have the schematic (a rather poor xerographic copy). I'll try to get a usable scan of it. Stay tuned.

Reply to
Michael

That would be great, thanks. :-)

Reply to
rgb-man

Posted at alt.binaries.schematics.electronic Good luck.

I understand the lure of making use of free parts - I do it a lot myself

- but that old NMOS chip is such a bummer to program (source -> EEPROM

-> uC) that development on it can quickly get to you. I did two projects with the 68705 and got fed up. Moved to flash PICs, first the

16F84 and then the 16F628.
Reply to
Michael

Excellent, many thanks. :-)

Reply to
rgb-man

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