On Saturday 23 July 2016, 21:16:18 Gerrit Heitsch <email@example.com> wrote: > On 07/23/2016 09:08 PM, Segher Boessenkool wrote: > > On Sat, Jul 23, 2016 at 08:46:04PM +0200, Gerrit Heitsch wrote: > >> On 07/23/2016 08:22 PM, Segher Boessenkool wrote: > >>> On Sat, Jul 23, 2016 at 06:29:33PM +0200, Michał Pleban wrote: > >>>>> Next project would be a replacement 8501 since those also die > >>>>> easily... > >>>> > >>>> That should be much easier, as no analog stuff (video) is needed and a > >>>> 6502 core is easily obtainable... Somebody should really make such > >>>> project :-) > >>> > >>> The visual6502 project has a die picture of an 8501. From the picture > >>> it seems clear that both the 8500 (c64c) and 8502 (c128) used the same > >>> silicon, with different contacts bonded out. > >> > >> You sure? The 8501 is missing Port-Bit 5. It's not only not bonded out, > >> it's not present, you can't set it while the 8500 has all the port bits, > >> you can set them. > > > > (bit 5? Do you mean bit 7?) > > No, the 8501 is missing Bit 5, Bit 6 and 7 are present and used. They > are used as inputs from the IEC bus. I assume since that makes is easy > to use the BIT command or ROL/ASL for serial/parallel conversion. > > > Why do you think you can set all port bits on the 8500? > > Because people have been trying to use Bit 6 and 7 to determine CPU > temperature or detecting a 6510 or 8500 from the time it takes a 1 to > become a 0 when switching the port from output to input. see https://sourceforge.net/p/vice-emu/code/HEAD/tree/testprogs/CPU/cpuport/ ... there is another testprog in the repo which tries to determine the type of CPU by checking the cpu port - however that one does NOT work correctly: https://sourceforge.net/p/vice-emu/code/HEAD/tree/testprogs/CPU/cputest.txt (corrections/improvements welcome) -- http://www.hitmen-console.org http://magicdisk.untergrund.net http://www.pokefinder.org http://ar.pokefinder.org PROGRAM n. A magic spell cast over a computer allowing it to turn one's input into error messages. tr.v. To engage in a pastime similar to banging one's head against a wall, but with fewer opportunities for reward. Message was sent through the cbm-hackers mailing listReceived on 2016-07-23 20:00:48
Archive generated by hypermail 2.2.0.