I found a few note that maybe of help... http://bitsnbikes.blogspot.com/2010/11/hardware-single-step-for-8085.html
http://www.vintage-computer.com/vcforum/archive/index.php/t-22195.html http://www.brielcomputers.com/phpBB2/viewtopic.php?t=449&start=0 http://www.s100computers.com/Hardware%20Folder/CompuPro/CPU8085-88/CPU85-88.htm http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=5&ved=0CDQQFjAE&url=http%3A%2F%2Fwww.classiccmp.org%2Fdunfield%2Fs100c%2Fgodbout%2Fcpu8588.pdf&ei=J2ZvVOTWAsfUoATw5YKgBQ&usg=AFQjCNE7ZBpX7DYOttn425XJfBWMK0xuFA&bvm=bv.80185997,d.cGU&cad=rja On Thu, Nov 20, 2014 at 7:06 PM, Crusty OMO <[email protected]> wrote: > The only trouble I see with going to the 8085, is the loss of the status > byte. It can be partially recreated by decoding the state lines, which > have to be done anyway to differentiate I/O vs Memory access. But a > "Stack" and "Inte" signal can not be gotten. > > The main purpose of this board was to be compatible with the front panels > of the ALTAIR and IMSAI. > > Does the group want to drop that *full* compatibility and go with an 8085 > board? I put it to a vote. > > The 8085 can function with limited functionality with the front panels. > Here's a break down of the front panel and what's loss. > + indicates signal can be produced > > STATUS BUS > +MEMR > +INP > +M1 (fetch) > +OUT > +/WO > +HLTA > -STACK (no more indication of STACK operations, no big loss) > +INTA > > CONTROL BUS > -INTE (no indication of Interrupts enabled, no big loss either) > +HLDA > -WAIT (no indication of a WAIT mode... is that right? or am I missing > something in the data sheet?) > > Further, the RUN/STOP function will not stop on a M1 (Fetch cycle). this > will cause erratic behavior of the Examine/Next functions. Work around is > to single step to an M1 function then use "Examine". This might be the > biggest down fall of the 8085 CPU, but not the end of the world since the > Z80 had the same problem with the old front panels, and many didn't care > about it. > > I can't say we are losing much, but everyone has their own opinions of > what's important. > > I put it to a vote and/or discussion. > > Cheers, > Josh > > > > > > > ------------------------------ > From: [email protected] > Subject: Re: [N8VEM-S100:5635] Re: 8080a board > Date: Thu, 20 Nov 2014 10:33:20 -0500 > To: [email protected] > > > All good ideas, especially the 8085 and the sense switch input. I wish the > msdos board had a sense switch input. > > Sent from my iPhone > > On Nov 20, 2014, at 10:09 AM, Tom Lafleur <[email protected]> wrote: > > Some notes for Ver one... To gain some room on the board.... > > As suggested before.... > > Use only 4 wire rs232 with max232a/tr202, removing need for +-12v ( 3 to 4 > chip saving) > Move to 8085, no need for +12 or -5v, less support chip needed... ( ~2 > chip saving) > > Make board stand alone, no other boards needed to make it run... ( plus 1 > chip) > Fix upper address and data lines to bus issues . (Plus 2 chips) > > New ideas... > > Replace 8212's with 74als logic (~ 3 chip saving) > > Replace ram chips with one larger chip, (wasting part of the chip to save > room if needed) 64k x 8 or larger like an as6c4008 with a poor man's mmu if > their room on board...(use output port?) like zeta board.... (~ plus 1 to > 2 chip saving) > > If room, allow room for a dip switch with pull-ups on input port.... (~ > plus 1 chip) > > > Just my ideas from building the board.... > > > > > > i~~ _/) ~~~~ _/) ~~~~ _/) ~~~~ _/) ~~i > > Tom Lafleur > > > On Nov 19, 2014, at 8:00 PM, Crusty OMO <[email protected]> wrote: > > Opps, thanks for letting me know... I guess it's a cut n paste error or > just an over sight. > > > ------------------------------ > Date: Wed, 19 Nov 2014 16:34:41 -0800 > Subject: 8080a board > From: [email protected] > To: [email protected] > > fyi... > > > It appears that UART1 at A5 is connected to COM1 port, P1/P2 on the > board, but the schematic say its connected to P3/P4 > > -- > > ~~ _/) ~~~~ _/) ~~~~ _/) ~~~~ _/) ~~ > > Tom Lafleur > > > -- > 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. > > > -- > 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. > > -- > 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. > -- ~~ _/) ~~~~ _/) ~~~~ _/) ~~~~ _/) ~~ Tom Lafleur -- 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.
