[solved] Anyone know about an old Motorola SC85180G CPU? - Page 1
Forum section: electronics / general

author: rhodges
author_rank: Frequent Contributor
timestamp: August 14, 2019, 07:46:57 pm
content: I have many dozens of old bar code reader boards with nice aluminum (eh, "aluminium") cases. They have EPROM, RS232, beeper, and 5-pin DIN plug and socket. And a bar code wand.And a Motorola CPU that is marked SC85180G. I can't seem to find any data on it. The boards are marked "TPS ELECTRONICS COPYRIGHT 1989" (1987 in a different spot).It would be nice if I (or anyone else) could use these for some project. But without more information, they are just a few almost-useful parts and a lot of garbage.Searching for SC85180G got me very few actual mentions, and no useful info. Maybe this is a special code for one of their other chips, like 6805, 6811, or 6802?Thanks!

author: legacy
author_rank: Super Contributor
timestamp: August 14, 2019, 08:17:43 pm
content: we can try to identify the architecture by the analyzing the firmware on the epromMotorola had the bad habit of customizing chip for big customers. I have a lot of 683xx chips made for Ford-Racing, they are 683xx chips with custom firmware in a masked ROM, but they do not have the label "683xx" on the chip but rather weird letters that make no sense according to any user manual.I know that they are 683xx chips because I dumped the firmware, and IDA v6.6 recognized it as 68k.

author: legacy
author_rank: Super Contributor
timestamp: August 14, 2019, 08:19:33 pm
content: The same applies to some 68hc11 chips sold by Motorola to IBM for their hard drive controllers (PC-IBM, i286).

author: rhodges
author_rank: Frequent Contributor
timestamp: August 14, 2019, 09:12:01 pm
content: Quote from: legacy on August 14, 2019, 08:17:43 pmOkay, that sounds like a good idea. Maybe run the code through various disassemblers and see which output looks like real code.

author: rhodges
author_rank: Frequent Contributor
timestamp: August 14, 2019, 11:54:26 pm
content: While I am figuring this out... If anyone else would like to look at the code, I put the binary here:www.hodges.org/rh/barcode_epromSince there is no 74x138 decoder on the board, I think the 2764 EPROM may be enabled for all addresses. The top 16 bytes are programmed, and they might be the reset code.All hints and ideas welcome!Thanks!

author: amyk
author_rank: Super Contributor
timestamp: August 15, 2019, 02:48:00 am
content: The 8 vectors at the end hint at this being 68xx family, and disassembling it as 6811 code with the image mapped at E000 makes sense (reset vector at E359), so I'm guessing that could be it. A 6812 is too new, and trying to interpret the code as 6809 doesn't make as much sense.Edit: I found this other interesting product that appears to have the same CPU:https://gridchoice.com/shop/apple/6769-used-mystery-circuit-board-apple-transporter-corvus-systems.html--- searching "Corvus Systems Apple Transporter" yields some more related info, includingthis imagewhichcontrasts with this oneshowing a HD6801 in place of the SC85180G......and more digging reveals another Motorola chip used in a Corvus product, this time an SC85337P:https://atariage.com/forums/uploads/monthly_03_2011/post-27823-0-18396400-1300871195.jpgSame package, same 10MHz oscillator, slightly different markings...

author: rhodges
author_rank: Frequent Contributor
timestamp: August 15, 2019, 12:00:27 pm
content: Yes, this is looking like a 6801/6803 CPU. I am reading the datasheet, and it shows a 74LS373 to latch address lines, and yes, the board has one between the CPU and EPROM. The datasheet has a table with 3 crystal choices for the serial baud rate, one of them 4.9152 mhz. That is on the board. I used a 6801 disassembler on the binary, and so far it looks okay.If I verify that pins P20, P21, and P22 have resistors to set "mode 2", then I will assume it is a 6801 (ROM disabled) or 6803 (no internal ROM).Thanks!

author: amyk
author_rank: Super Contributor
timestamp: August 16, 2019, 12:14:11 pm
content: I thought it was a 6811 at first because after further comparison of the opcode maps, the 6800/1/3/11 all have a common ancestor starting with the 6800, but the 6805 and 6809 are very different from that series and each other. I looked again and 6801 does make sense.

author: rhodges
author_rank: Frequent Contributor
timestamp: August 16, 2019, 03:00:25 pm
content: I have worked (played) with the 6805, and I know it has its own program memory. I am pretty sure it is the same with the 6811. I looked at the 6804, and they all have lower pin counts (no 40 pin version). The 6802 has the xtal pins on the wrong side.Points in favor of 6801/6803:Vcc, Vss in right place.Xtal pins in right place.Serial in/out pins in right place (traced to RS232 chip).74LS373 latch is between CPU and EPROM, just like in the datasheet.Disassembly looks okay at first glance.(Reset vector looks like it sets up ports.)I will look at the serial interrupt and see if the code accesses the serial register.Not sure:P20 and P22 seem to be floating, needed for mode setup. P21 has pull-up.

author: rhodges
author_rank: Frequent Contributor
timestamp: August 16, 2019, 07:14:38 pm
content: I have used some of these boards for parts, and I found a few of them. Aha! Two boards have Motorola 6803 and two have Hitachi 6803!Mystery solved.