Hallo Olaf, Aan 20-03-98 21:45, in bericht <199803202045.VAA19958@vitellius.mbfys.kun.nl>, Olaf Seibert <firstname.lastname@example.org> schreef: > Yes, in the PETs, NO! > and basically also in the 64, YES > most signals (but I > don't think ALL signals) go OUT though an inverter but they come IN > without an inverter. PETs NO again, 1541 YES. > I'm sure that's needed somehow electrically. To NPN transistors behave better and quicker for some reasons then PNPs. It has something to do with quantum mechanics I was told so don't ask me further :-) > compensate for that, the software inverts the signals again. On top of > that, some signal names have another inversion in them: NRFD, NDAC... > (NOT ready for data, NOT data accepted) All this can be very confusing. The word NOT has nothing to do with the active level of the signal. The 6502 has a active (L) RESET input. The 8255 has an active (H) input line. > While we're dreaming: not only PCs have ISA slots, so if possible don't > do anything that depends on PCs unnecessarily. A bus is a bus is a bus. At this moment I need addresslines, a databus, a read- and a write-line and a line to slowdown the guest system. Except the last line the others can be found on every bus I know. The ZX Spectrum does NOT have the slowdown line and cannot be used for this purpose. Andre has a Atari and he could tell us if this machine has such a line at his slot. Even if the machine does not have this line, you can create one. The only reason I don't mention this in the first place is that I want to keep the machines as original as possible. In this way you make it also interesting for people who don't want anybody to touch their precious computer with a solder iron. Groetjes, Ruud
Archive generated by hypermail 2.1.1.