I think doubling the speed of the processor might be too much however. I know that is convenient - to make a /2 circuit. It is an experiment. I found the original OKI datasheet for MSM80C85ARS indicates that it can support a clock period of 320 nsec minimum. There are faster processors that are rated down to 200 nsec and 125 nsec.
On Thu, Nov 26, 2015 at 8:11 AM, Stephen Adolph <twospru...@gmail.com> wrote: > I'd want to take a look and understand how the downstream parts would > react to the faster I/O and memory timing. The RAM and ROM systems are > basically asynchronous - they look for edges and respond accordingly. So > long as they are fast enough it should be ok. > The PIO chip - unclear there, but I bet it would work > > > On Thu, Nov 26, 2015 at 3:53 AM, Georg Käter < > georg.kae...@gk-engineering-services.de> wrote: > >> Dear all, >> >> thank you for your comments/ideas. I´ll do further investigations in that >> matter. Maybe M100 >> can run CPU @ 9,8304MHz outer clock, related systemclock @pin 37 has then >> just to be >> divided by 2 through a 74LS293 or equal to feed the PIO and further >> components with the >> "old" base clock. >> What´s your opinion about this? >> >> Kind regards >> Georg Käter >> >> >> On Nov 25, 2015 11:55 AM, "Alex ..." <abortretryf...@gmail.com> wrote: >> >> The cassette routines will probably be broken by this too, though you >> might be able to "overclock" the tape recorder (or MP3 file) to match. :) >> On Nov 25, 2015 9:43 AM, "Stephen Adolph" <twospru...@gmail.com> wrote: >> Hi Georg, >> Very interesting! I think there could be impact on sounds as well. >> Tundra semiconductor made a processor capable of 10MHz also. I have not >> yet played with that. >> It could be possible to make an adapter that includes a /4 circuit to >> feed correct clock to the UART, and also the 81C55. >> This is an interesting idea, worth exploring. >> Steve >> >> On Wed, Nov 25, 2015 at 9:33 AM, Georg Käter < >> georg.kae...@gk-engineering-services.de> wrote: >> Hello together, >> >> I did some try out on overclocking the 80C85 in my M100. I was quite >> successful using an oszilator >> with 7,3728MHz which gives a CPU clock 50% higher than the original one. >> My M100 run with this >> w/o any issues in running BASIC so far, gain in performance is visible >> and amazing. But there is one thing >> you might have an solution or even idea how to solve for. TELCOM and any >> program communicating via >> serial port are not working as PIO 81C55 gets the clock from CPU which is >> now 50% above the original >> value. >> Any comment from you is welcome >> >> Kind regards >> Georg Käter >> >> >> ---------- Forwarded message ---------- >> From: "Alex ..." <abortretryf...@gmail.com> >> To: Model 100 Discussion <m100@lists.bitchin100.com> >> Cc: >> Date: Wed, 25 Nov 2015 11:55:39 -0500 >> Subject: Re: [M100] M10X/T200: Overclocking CPU >> >> The cassette routines will probably be broken by this too, though you >> might be able to "overclock" the tape recorder (or MP3 file) to match. :) >> On Nov 25, 2015 9:43 AM, "Stephen Adolph" <twospru...@gmail.com> wrote: >> >>> Hi Georg, >>> Very interesting! I think there could be impact on sounds as well. >>> Tundra semiconductor made a processor capable of 10MHz also. I have not >>> yet played with that. >>> It could be possible to make an adapter that includes a /4 circuit to >>> feed correct clock to the UART, and also the 81C55. >>> This is an interesting idea, worth exploring. >>> Steve >>> >>> On Wed, Nov 25, 2015 at 9:33 AM, Georg Käter < >>> georg.kae...@gk-engineering-services.de> wrote: >>> >>>> Hello together, >>>> >>>> I did some try out on overclocking the 80C85 in my M100. I was quite >>>> successful using an oszilator >>>> with 7,3728MHz which gives a CPU clock 50% higher than the original >>>> one. My M100 run with this >>>> w/o any issues in running BASIC so far, gain in performance is visible >>>> and amazing. But there is one thing >>>> you might have an solution or even idea how to solve for. TELCOM and >>>> any program communicating via >>>> serial port are not working as PIO 81C55 gets the clock from CPU which >>>> is now 50% above the original >>>> value. >>>> Any comment from you is welcome >>>> >>>> Kind regards >>>> Georg Käter >>>> >>> >>> >> >
