On 2014-04-29 2:16 AM, Gerrit Heitsch wrote: > On 04/28/2014 11:26 PM, smf wrote: >>> Probably running the 1571, and by extension, the CIA in it, at 2 MHz. >>> Even when running the C128 at 2 MHz, the CIAs will still be clocked at >>> 1 MHz. >> >> I wonder why they run the CIAs in the 1571 at 2Mhz., but the C128 only >> ever 1Mhz. > > Maybe they were not able to make enough of them that could run at 2 MHz. > That way, they could use all CIAs for the C128. > > Also, you get timers that always run the same speed, no matter what the > CPU is clocked at. And, the PC handshaking line is pulsed for one system-clock cycle when port B is accessed. Many devices from that time period expect those strobes to last at least 1 microsecond. They can't see shorter pulses. Message was sent through the cbm-hackers mailing listReceived on 2014-04-29 17:00:03
Archive generated by hypermail 2.2.0.