OK very interesting... that kind of compare and contrast of the two interrupt controller boards was exactly what I needed
Sure, that would be interesting to experiment with. Put me down for Qty 2 on the next order. On Tuesday, June 3, 2014 12:13:43 PM UTC-5, monahanz wrote: > > The 8259A on the PIC/RTC board can work in “status poll” mode with a > Z80. The 8259A will not work (without some very tricky hardware circuits > involving the chip itself, putting DMA states on the bus and modifying the > Z80 board) with a Z80. This has to do with how Intel programmed the 8259A > to responds to an INTA signal. (oversimplifying, it puts back on the bus > two INT vectors). The Zilog chips expect one. Alternatively you could > use the AMD’s 9519 where the number of returned INTS was programmable (1, 2 > or 3). However both the Zilog and AMD chips are quite different in their > software interface ( and not compatible with a generic MS-DOS disk). Thus > the name “MSDOS support board”. Of course the above board will work fine > with the 8086 etc. CPU’s > > > > The Z80 for and 8 bit CPU actually has a powerful interrupt structure. The > S-100 PIC/RTC board actually allows it to be utilized. It is summarized > here:- > > > http://s100computers.com/My%20System%20Pages/PIC&RTC%20Board/My%20PIC%20Board.htm > > > > As to RTC, clearly no problem, it’s just a series of ports to the Z80. > Though again the MSDOS support board utilizes a PC compatible RTC (local > RAM) and timer. > > > > Hope the above helps. > > John > > > > > > > > > > > > *From:* [email protected] <javascript:> [mailto: > [email protected] <javascript:>] *On Behalf Of *yoda > *Sent:* Tuesday, June 3, 2014 7:02 AM > *To:* [email protected] <javascript:> > *Subject:* [N8VEM-S100:3928] Re: S-100 PIC/RTC Board Production > > > > This would be good for the 68K board if you want to do other than CPM 68K. > Could be used in port of emuTOS and uCLinux - necessary for multi-tasking > systems. > > On Tuesday, June 3, 2014 8:57:00 AM UTC-5, Vince Mulhollon wrote: > > On Tuesday, June 3, 2014 8:08:32 AM UTC-5, Edward Snider wrote: > > Are there many people interested in this board? If there is enough > interest (20 boards) I can handle a run of these. > > > My interpretation of the board is its a non-msdos compatible msdos support > board. I'm curious if there's any software, features, compatibility, > advantages of this specific board. So the XYZ board only works with the > PIC/RTC board and not the MSDOS support board because of ... > > They are both basically 8259 plus a RTC, right, I think? And the msdos > board adds the keyboard hardware and msdos timers, right? > > I'm unclear on this and that would help me figure out if I want one of > these. > > -- > You received this message because you are subscribed to the Google Groups > "N8VEM-S100" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] <javascript:>. > For more options, visit https://groups.google.com/d/optout. > -- You received this message because you are subscribed to the Google Groups "N8VEM-S100" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
