On 11/05/2016 09:37 PM, didier derny wrote: > while checking some signals on the 6502 of my 8032 motherboard > I found the 'high' level rather low 2.5v (I expected around 4v...) > > so I took my SYM1 board and tested several 6502 > MOS 6502 around 4v > Rockwell 6502 around 4v > Rockwell 65c02 around 5v > Synertek 6502 around 2.5v > CM630 around 4v (bulgarian clone) > > I tried several 6502 of each type... Since I was curious and able to test it... A few years ago I built myself a replica of the EMUF232 on a perfboard (was a real pain in the...). That's a 6502 system with 2 x 6522, 1 6551, 32KB RAM running at 1.8432 MHz. As a CPU I used a SY6502A, datecode 8047. When checking the address lines on the scope today, the CPU produces a HIGH of 3.5-3.7V. So it can't be Synertek in general unless the drivers are less powerful than Rockwell and MOS and your board has more load on the lines. If possible, check the SY6502 in another board, maybe a 1541. Gerrit Message was sent through the cbm-hackers mailing listReceived on 2016-11-06 15:00:02
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