How To Copy/Clone Program from a MC6802 - Page 1
Forum section: electronics / general

author: NY2KW
author_rank: Regular Contributor
timestamp: August 10, 2019, 02:52:58 am
content: I have a control board from a 30+y amateur radio that uses a DIP-40, MC6802P. Is it possible to read all of the program hex and reprogram a new MC6802P? What would I need to do this?thanks in advanceJerry NY2KW

author: oPossum
author_rank: Super Contributor
timestamp: August 10, 2019, 02:59:59 am
content: There isn't any non-volatile memory in a 6802. Probably a 2700 series EPROM on the board that has the code.

author: james_s
author_rank: Super Contributor
timestamp: August 10, 2019, 05:17:26 am
content: The 6802 may be paired with a 6846 which is a ROM/IO/Timer. I haven't dealt with that particular part before but if it is used here it should be fairly easy to wire up an adapter to read it using a standard EPROM programmer.

author: rhodges
author_rank: Frequent Contributor
timestamp: August 10, 2019, 10:36:30 am
content: If you would like to experiment with 6802 programming on a separate board, let me know. I havea lot offour boards with 6802, EPROM, other logic, and connectors. They used to bebar code scanners"Foot Mouse" that plugged into a PC keyboard port.

author: NY2KW
author_rank: Regular Contributor
timestamp: August 11, 2019, 02:28:45 am
content: Yes, there is a 24 pin ROM but custom lettering... how can I figure out what kind of ROM or EPROM or is there a generic reader I could use non-destructively?Jerry

author: edavid
author_rank: Super Contributor
timestamp: August 11, 2019, 03:22:32 am
content: Quote from: NY2KW on August 11, 2019, 02:28:45 amIt could be a 2716 or 2732 EPROM, or an 8Kx8 mask ROM. Post a photo here.

author: NY2KW
author_rank: Regular Contributor
timestamp: August 11, 2019, 05:05:06 am
content: Here is a picture.. the board only uses one of these, one got corrupted so I want to back up remaining one.Thanks for your helpJerry

author: PCB.Wiz
author_rank: Super Contributor
timestamp: August 11, 2019, 09:57:42 am
content: Quote from: NY2KW on August 11, 2019, 02:28:45 amCheck what voltages it has during normal operation, likely it is just a simple +5V and GND.If it is simple supply, any EPROM programmer can read it if you connect the right address lines.You may need to check the connection wiring with a multimeter to decide what pinout to choose.Sourcing a 24 pin EPROM may be a challenge, but you should be able to find 28 pin EPROM, or Flash/MTP parts and use a simple socket adapter.

author: rhodges
author_rank: Frequent Contributor
timestamp: August 11, 2019, 11:44:37 am
content: QuoteI can spare 10 2716 or 2 2732 EPROMs to anyone who needs them.OOPS! I made a mistake about the 6802 boards!The boards for the bar code reader have a Motorola SC85180 CPU. I could not easily find info on that.The 6802 boards are for a "Foot Mouse" and I only have 4 of them. They have a 6802, 2716, 6821, two ls74an, and a 7406. There is a 4-pin RJ12 jack for the "mouse" and a 5 pin DIN for keyboard connection. Pictures here:http://www.hodges.org/rh/footmouse/footmouse1.jpeg(board)http://www.hodges.org/rh/footmouse/footmouse2.jpeg(case)

author: NY2KW
author_rank: Regular Contributor
timestamp: August 11, 2019, 12:31:48 pm
content: The board only has a +5vdc supply. I believe the symbol on the chip looks like Motorola... can anyone confirm? If so, wouldn't all 24 pin EPROMs from Motorola around 1980 have the same pin-out for address lines, etc?

author: Andy Watson
author_rank: Super Contributor
timestamp: August 11, 2019, 12:43:23 pm
content: I think the symbol on the chip is Rockwell. But yes, it will almost certainly have a common pin-out. Any discrepancy will be around the Chip-Enable and higher order address lines - you could probably figure most of this out by tracing the circuit. What is the radio? Can you find the schematic fo it?

author: NY2KW
author_rank: Regular Contributor
timestamp: August 11, 2019, 01:48:24 pm
content: I am a dunce... attached is the schematic. The radio is a Collins Rockwell HF-380 which is general transceiver covering 1.6 - 30MHz. There are many programmed ROMs available for the amateur radio version KWM-380 (only covers amateur HF bands) that I plan to use to master the cloning process before I venture to clone the HF-380 ROM of which I only have one. Any idea which Rockwell ROM this might be or whether there are any other substitutes?

author: bd139
author_rank: Super Contributor
timestamp: August 11, 2019, 02:09:58 pm
content: Looks like standard footprint 2716 EPROM / PROM. I'd use a 2716 in there. Loads on ebay for nothing checked and blanked.

author: oPossum
author_rank: Super Contributor
timestamp: August 11, 2019, 02:11:39 pm
content: Rockwell R2316B mask ROM. Equivalent to Intel 2316A/8316A and possibly others.These ROMs had programmable chip select, so some are mostly compatible with the common 2716, while others require changes to the chip select logic.The schematic shows pins 18 & 21 grounded. A 2716 will require pin 21 connected to Vcc. It may be necessary to invert pin 20, but that is unclear from the partial schematic.

author: amyk
author_rank: Super Contributor
timestamp: August 11, 2019, 06:34:19 pm
content: The pinout matches, but how did you get from the R1453 marking to R2316B?

author: oPossum
author_rank: Super Contributor
timestamp: August 11, 2019, 06:38:20 pm
content: It is the only Rockwell part I know of that matches the pinout.

author: james_s
author_rank: Super Contributor
timestamp: August 11, 2019, 06:41:38 pm
content: Since you have the schematic, it's trivial to wire up an adapter to read the chip in something like a TL866 or any other EPROM reader/burner. All you need to do is compare the pinout to something standard like a 2716, most of the pins should all line up 1:1, the chip select line can be tied to Vcc or Gnd depending on what it needs. You can either measure what it is in system or you can tie it to one, try reading the chip and if you get all FF's tie it to the other.

author: PCB.Wiz
author_rank: Super Contributor
timestamp: August 11, 2019, 08:33:55 pm
content: Quote from: NY2KW on August 11, 2019, 01:48:24 pmROM parts you cannot re-program.You need either a EPROM, or a MTP EPROM (Multi-time programmable EPROM) or a FLASH part.As mentioned above, 27C16 EPROMS are available on Chinese web sites, but you may need to verify that chip-select polarity & VppYou could make an adapter board, that uses a FLASH part (eg PLCC32 SST39VF010-70-4C-NHE is cheapest easy package flash on DK) and that would allow multiple copies of code choice

author: james_s
author_rank: Super Contributor
timestamp: August 11, 2019, 09:01:19 pm
content: Once step at a time though, first thing to do is make a successful dump of the code, then you can make an adapter to use a standard EPROM or flash chip in its place. This is a fairly straightforward project, if you were local I'd offer to wire up an adapter and dump the chip for you. I have dealt with this sort of thing quite a few times working with vintage arcade machines.