Re: Sv: K6/3 on 3.2-STABLE - PROBLEM SOLVED
Matthew Dillon wrote: > > : > :Back around 1980, I overclocked my 5MHz z80 to 6MHz. It worked without > problems, except that for-next loops in comal didn't exit as expected. That > was also reproducible... > : > :Leif > > In the early 90's I regularly ran 10 MHz 68000's at 20 MHz (which was > about the limit the dynamic ram at the time could handle). > > When motorola started phasing out the DIP version of the 68000 after > many years of good service, one of their big customers noted that Motorola > had updated the process many times but had never updated the timing specs > during virtually the entire life of the product, and wanted to know how > fast the chip could actually be run. > > So Motorola tested it. I believe the 12.5 MHz spec'd chip tested > to 80 MHz. Not bad! I used to work on an embedded system that used the 16 Mhz 68EC000, and we encountered a situation where we needed to raise the clock to 20Mhz. We substituted a couple of 40 Mhz crystals for the 32 Mhz crystals and it worked fine. The next three boards we tried didn't work at all. We called Motorola and asked about 20 Mhz parts. They were on the verge of releasing them, so we asked for samples. They shipped us 20 parts directly out of factory test in south-east asia. The only difference between the 16 and 20 Mhz parts were the worst-case timing. -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC http://softweyr.com/ w...@softweyr.com To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-hackers" in the body of the message
Re: Sv: K6/3 on 3.2-STABLE - PROBLEM SOLVED
Matthew Dillon wrote: > > : > :Back around 1980, I overclocked my 5MHz z80 to 6MHz. It worked without problems, >except that for-next loops in comal didn't exit as expected. That was also >reproducible... > : > :Leif > > In the early 90's I regularly ran 10 MHz 68000's at 20 MHz (which was > about the limit the dynamic ram at the time could handle). > > When motorola started phasing out the DIP version of the 68000 after > many years of good service, one of their big customers noted that Motorola > had updated the process many times but had never updated the timing specs > during virtually the entire life of the product, and wanted to know how > fast the chip could actually be run. > > So Motorola tested it. I believe the 12.5 MHz spec'd chip tested > to 80 MHz. Not bad! I used to work on an embedded system that used the 16 Mhz 68EC000, and we encountered a situation where we needed to raise the clock to 20Mhz. We substituted a couple of 40 Mhz crystals for the 32 Mhz crystals and it worked fine. The next three boards we tried didn't work at all. We called Motorola and asked about 20 Mhz parts. They were on the verge of releasing them, so we asked for samples. They shipped us 20 parts directly out of factory test in south-east asia. The only difference between the 16 and 20 Mhz parts were the worst-case timing. -- "Where am I, and what am I doing in this handbasket?" Wes Peters Softweyr LLC http://softweyr.com/ [EMAIL PROTECTED] To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Re: Sv: K6/3 on 3.2-STABLE - PROBLEM SOLVED
: :Back around 1980, I overclocked my 5MHz z80 to 6MHz. It worked without problems, except that for-next loops in comal didn't exit as expected. That was also reproducible... : :Leif In the early 90's I regularly ran 10 MHz 68000's at 20 MHz (which was about the limit the dynamic ram at the time could handle). When motorola started phasing out the DIP version of the 68000 after many years of good service, one of their big customers noted that Motorola had updated the process many times but had never updated the timing specs during virtually the entire life of the product, and wanted to know how fast the chip could actually be run. So Motorola tested it. I believe the 12.5 MHz spec'd chip tested to 80 MHz. Not bad! -Matt Matthew Dillon To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-hackers" in the body of the message
Sv: K6/3 on 3.2-STABLE - PROBLEM SOLVED
> > > > After rechecking all the jumpers it turns out that the supplier > > had set the core voltage to 2.2V instead of 2.4V! > > Interesting that the error was reproducible, if this was the cause of > it. The problem never varied from that exact point? I'd like to say > that I find that a testament to the precision of modern computer > hardware, but I'm still having trouble believing that the incorrect > voltage setting caused a specific, always-reproducible problem. > > Greg Back around 1980, I overclocked my 5MHz z80 to 6MHz. It worked without problems, except that for-next loops in comal didn't exit as expected. That was also reproducible... Leif To Unsubscribe: send mail to majord...@freebsd.org with "unsubscribe freebsd-hackers" in the body of the message
Re: Sv: K6/3 on 3.2-STABLE - PROBLEM SOLVED
: :Back around 1980, I overclocked my 5MHz z80 to 6MHz. It worked without problems, :except that for-next loops in comal didn't exit as expected. That was also :reproducible... : :Leif In the early 90's I regularly ran 10 MHz 68000's at 20 MHz (which was about the limit the dynamic ram at the time could handle). When motorola started phasing out the DIP version of the 68000 after many years of good service, one of their big customers noted that Motorola had updated the process many times but had never updated the timing specs during virtually the entire life of the product, and wanted to know how fast the chip could actually be run. So Motorola tested it. I believe the 12.5 MHz spec'd chip tested to 80 MHz. Not bad! -Matt Matthew Dillon <[EMAIL PROTECTED]> To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
Sv: K6/3 on 3.2-STABLE - PROBLEM SOLVED
> > > > After rechecking all the jumpers it turns out that the supplier > > had set the core voltage to 2.2V instead of 2.4V! > > Interesting that the error was reproducible, if this was the cause of > it. The problem never varied from that exact point? I'd like to say > that I find that a testament to the precision of modern computer > hardware, but I'm still having trouble believing that the incorrect > voltage setting caused a specific, always-reproducible problem. > > Greg Back around 1980, I overclocked my 5MHz z80 to 6MHz. It worked without problems, except that for-next loops in comal didn't exit as expected. That was also reproducible... Leif To Unsubscribe: send mail to [EMAIL PROTECTED] with "unsubscribe freebsd-hackers" in the body of the message
