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DavidMil

Looking for a working 835 modem...

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Any body have a working 835 modem (in the USA) that they are willing to sell/rent/loan me for a few weeks? I need to make a copy of the

1k ROM on the MPU so I can fix a couple of others I have. I don't mind sending a security deposit for the use of the modem too.

Or if someone knows where I could find a working 835 please let me know!

 

Thanks,

David Milsop

Kingwood, Texas

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I've talked to Brad at Best and he said they are totally sold out. B&C doesn't have one listed, but I haven't talked to anyone there

yet. I would be pleased and willing to pay someone for an image of the 1K of ROM that the 8048 had. The thing is, Atari used this chip in other

devices as well. I know for sure that the 1027 had one. So the chip has to come out of an 835.

 

DavidMil

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The Best Electronics website does list the MPU for the 835(under custom ICs), but you would need to confirm with Brad if it contains the proper firmware.

 

CO60549 (835 MPU) $15.00

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The Best Electronics website does list the MPU for the 835(under custom ICs), but you would need to confirm with Brad if it contains the proper firmware.

 

CO60549 (835 MPU) $15.00

 

I have an 835 and Dropcheck's ROM burner - if that can handle it I'll dump it for you.

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According to the 835 schematic there is no separate ROM, there would only be the 1kB ROM integrated into the 8048 MPU.

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I have one that I could send you, if you're still looking. For free (minus power supply). I can't test it, but the light turns on when I flick the power switch. 😀

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I got the 835 board and I'll test it out tonight. Is there something I can help you with?

 

Thanks again,

David Milsop

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I got a good P8048 MPU chip and I now have two working 835 modems and I fixed gamer-stu's modem too. I tested them with Atari's CPS Diagnostic Disk FD100577 (Rev 02).

 

Thanks to all!

David Milsop

Kingwood, Texas

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Please share the ROM dump so that it could be publicly preserved. Thanks.

Edited by ijor
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I have a Universal Programmer that does 8048's if you're interested.

 

Hopefully, it isn't copy protected.

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I got a good P8048 MPU chip and I now have two working 835 modems and I fixed gamer-stu's modem too. I tested them with Atari's CPS Diagnostic Disk FD100577 (Rev 02).

 

Thanks to all!

David Milsop

Kingwood, Texas

Please post a dump of the ROM, I have two that need fixing too :)

 

I have a Universal Programmer that does 8048's if you're interested.

 

Hopefully, it isn't copy protected.

Which Programmer is that? My Willem will do P8048AH, not sure if that is the same type of MCS?

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Yeah, we need to dump all the Atari 8048 code. I'm pretty sure there's info online for dumping even the protected ones.

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Please post a dump of the ROM, I have two that need fixing too :)

 

Which Programmer is that? My Willem will do P8048AH, not sure if that is the same type of MCS?

I'll have to double check, but I believe my Sunrise Z-1000b will do them.

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Please remember that the 8048 is not a ROM chip it is a MPU with 1K of ROM built into it. I would doubt very seriously that you could copy protect it.

The ROM was dumped to a D8748 EPROM (which is a pin for pin compatible version of the 8048 MPU chip).

 

David

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I know what an 8048 is, just wasn't sure if it supported protection. Protection goes back to at least PALs

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Seems there is no protection support on the 8048. But many MCU devices support firmware protection. Some based on masked ROM don't have any kind of external bus interface, other than I/O ports. So you simply have no external way to access the firmware. Other devices, usually using OTP (One Time Prom), have a firmware that could be written externally, but it couldn't be read back. I don't remember when the first devices with firmware protection by design were available.

Edited by ijor

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Kyle should be able to read it and write it.... so it would be cool to let him do it... the resulting post should include not only the code but maybe a side note on what programmers/requirements that will write it for the future

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Well, I thought my Sunrise programmer did 8048's, but I got it out and fired it up, and no 8048's on the list.

 

I'm going to look for one that does them.

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Yesterday I ordered a 8048 adapter for my Willem board from This Place for only $4 plus shipping

 

I'll be able to read them, plus burn them :) I'll post the dump as soon as the adapter arrives...

DavidMil will not be able to post the ROM dump of the 835 as someone who donated a 8048 for him to check out doesn't want to share it (the ROM Dump) :?

Edited by AtariGeezer

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