Can we have the sense switch (IOBYTE) pegged to 0EFH to make life simple. Is used a lot in our earlier software.
John From: [email protected] [mailto:[email protected]] On Behalf Of Richard Cini Sent: Thursday, November 20, 2014 7:33 AM To: [email protected] Subject: Re: [N8VEM-S100:5635] Re: 8080a board 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.
