I asked Dave Esposito who was a long time layout person at MOS/CBM: Dave's comments are below except where I chimed in. The simple R1, R2, R3 means full layer revisions. The other numbers are layer revisions. Example 1: 6567R56A 6567 R5 6A Base part number Mask revision layer revision of the highest Metal layer This is the 5th full mask revision plus one more layer Metal 6 revision But that # is for identification only. In reality this part probably had a M6 VIA5 and M5 changed. They only list the highest layer rev. EXAMPLE 2: 8563R7A 8563 R7 A Base part number Mask revision I'm not sure what the A/B/C means. The 'A' could be packaging related. Ceramic vs plastic. But I'm really not sure. BilHerd->I think I saw this mean a backbias generator added once maybe a change of implant energy once. It could mean whatever the design team meant as long as they didn't think the masks could get mixed up in the process. Dave DiOrio got burnt on the VIC on the C128 when they inserted the desired mask to fix something and then inserted a mask from an older rev and brought back a problem. Also, after a while (when the chip was considered stable/bugfree?) MOS dropped the 'Rx' after the part number and only printed the part number on the IC. An indication that this chip was considered 'done'? Examples were the 6526, the 8520 and the 8500 which had R-Numbers at the beginning but then dropped them. Correct. Once the Part went into full production it was common practice to drop the Revision numbers. Sometimes it was even released as a new part number. Internally we knew it took (n) revisions to get it right. But the part number in production does not need to reflect that level of detail. -----Original Message----- From: email@example.com [mailto:firstname.lastname@example.org] On Behalf Of Gerrit Heitsch Sent: Monday, June 25, 2012 1:29 PM To: CBM Hackers List Subject: MOS chip revisions Hello, here's a question for Bil if he still remembers details... How did MOS pick the revision numbers printed on the ICs? The simple ones 'R1', 'R5' and so are not what I'm wondering about, but there were also rather strange numbers that fell out of the standard sequence like the 6567R56A or the 8563R7A and R9B or the 8566R3X. Also, after a while (when the chip was considered stable/bugfree?) MOS dropped the 'Rx' after the part number and only printed the part number on the IC. An indication that this chip was considered 'done'? Examples were the 6526, the 8520 and the 8500 which had R-Numbers at the beginning but then dropped them. Gerrit Message was sent through the cbm-hackers mailing list Message was sent through the cbm-hackers mailing listReceived on 2012-07-04 05:00:09
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