Hi Stephen, Updates are always welcome - You are not the only one :-)
Kindest regards, Doug Jackson em: [email protected] ph: 0414 986878 Check out my awesome clocks at www.dougswordclocks.com Follow my amateur radio adventures at vk1zdj.net ----------------------------------------------------------- Just like an old fashioned letter, this email and any files transmitted with it should probably be treated as confidential and intended solely for your own use. Please note that any interesting spelling is usually my own and may have been caused by fat thumbs on a tiny tiny keyboard. Should any part of this message prove to be useful in the event of the imminent Zombie Apocalypse then the sender bears no personal, legal, or moral responsibility for any outcome resulting from its usage unless the result of said usage is the unlikely defeat of the Zombie Hordes in which case the sender takes full credit without any theoretical or actual legal liability. :-) Be nice to your parents. Go outside and do something awesome - Draw, paint, walk, setup a radio station, go fishing or sailing - just do something that makes you happy. ^G ^G ^G ^G ^G ^G ^G ^G- In more laid back days this line would literally sing ^G ^G ^G ^G ^G ^G ^G ^G On Fri, 30 Oct 2020 at 09:12, Stephen Adolph <[email protected]> wrote: > update for the hardware geeks (I may be the only one?) > The first bottleneck is the data bus. > Swapping M2 for a faster 74LS245 yields *5MHz.* Of course this is bad > for current, so maybe there is a better CMOS part out there. > continued tweaking... > > > On Thu, Oct 29, 2020 at 12:52 PM Stephen Adolph <[email protected]> > wrote: > >> I have an early result on overclocking the M100. >> >> In my testbed I have a stock M100, with a couple of changes. >> 1) I have a socket on the 80C85 >> 2) the standard 2.45MHz clock is generated and fed to the system so that >> stays constant >> 3) I feed the CPU with a separate clock that can range from 2.5 to 8 MHz. >> 4) to overclock I use the Tundra 80C85 rated at 8 MHz. >> >> Initial results: >> The following clock rates worked stably: >> 2.47 MHz >> 2.74 MHz >> 3.09 MHz >> 3..53 MHz >> 4.11 MHz >> >> The M100 abruptly dies at 4.94 MHz. >> >> So at 4.11 MHz, the serial port worked fine. The only difference other >> than general speed, was that the audio tones were higher. >> >> I thought it would be faster to be honest. So maybe it is the 81C55. I >> happen to have a 5MHz rated device, lets try that. >> >> Answer = no. A 5MHz 81C55 does not improve things. So, it might be the >> RAM or ROM that is too slow, or who knows. >> >> Anyhow that seems to be the low hanging fruit. 4MHz. >> There are 80C85 out there that are rated at 5MHz, and the NSC800 can be >> had at 4MHz. >> >> ...Steve >> >> >> >> >>
