Of course I meant, "does not require an external ROM". On Friday, September 11, 2015 at 11:09:21 PM UTC-7, Andrew Bingham wrote: > > I posted a response over on the VCF forum John, but in case others here on > the -S100 list find it useful - http://geoffg.net/terminal.html is a very > nice PIC-based VT-100 monochrome VGA + PS/2 terminal that also doubles as a > serial-to-USB converter, with the Gerber files available on the site, > firmware, etc. The PIC is a smaller chip than the Propeller and does not > require an external RAM, you could go with (Z85C30 part of the Serial IO > board + this circuit) instead of the (most of the Propeller board + (8255 + > parallel->USB adapter chip part of the Serial IO board)) and it might save > some space on the board. Maybe even enough space left to run an SD card or > microSD card slot to the unused channel of the Z85C30 in synchronous mode > (SPI) to interface with the SD card? > > On Friday, September 11, 2015 at 9:03:14 PM UTC-7, monahanz wrote: >> >> Great source if info Bib >> >> Thanks >> >> John >> >> >> >> >> >> *From:* [email protected] [mailto:[email protected]] *On >> Behalf Of *Bob Bell >> *Sent:* Friday, September 11, 2015 1:20 PM >> *To:* [email protected] >> *Subject:* RE: [N8VEM-S100:7555] Re: A new Z80 based SBC to get >> beginners started on the S100 bus >> >> >> >> FWIW, I dug up the link to the serial terminal I referenced a couple of >> days ago in my SBC comments. >> >> This has a lot of possibilities and I have plans to build one of these as >> soon as I can find the time. >> >> It ought to be a great primer on programming the ATMega chips, which I >> have been keenly interested in. >> >> >> >> http://searle.hostei.com/grant/MonitorKeyboard/index.html >> >> >> >> Regards, >> >> >> >> Bob Bell >> >> >> >> >> >> *From:* [email protected] [mailto:[email protected]] *On >> Behalf Of *John Monahan >> *Sent:* Friday, September 11, 2015 1:07 PM >> *To:* [email protected] >> *Subject:* RE: [N8VEM-S100:7554] Re: A new Z80 based SBC to get >> beginners started on the S100 bus >> >> >> >> Thanks everybody for the suggestions. >> >> Here is what I’m currently going with and why… >> >> >> >> First and foremost I wanted a Z80 circuit that is proven and works with >> almost every vintage s100 board out there. I used the core circuit on our >> Z80 board ( >> http://s100computers.com/My%20System%20Pages/Z80%20Board/Z80%20CPU%20Board.htm >> >> ). It’s based on the old Intersystems II CPU board. I have not come across >> a vintage S100 board it does not work with. It goes to 10MHz in my own >> system of mainly S100Computers boards. Even works with DRAM boards. I had >> to remove the >64K windowing circuit for board space (see below). The Z80 >> to S100 bus signal conversions take up quite a few 74LSxx chips. Granted >> that could be reduced with a GAL or two but newcomers will probably not >> have experience programming GAL’s initially. >> >> >> >> Second, I brought in the circuit from the Propeller Console IO board ( >> http://s100computers.com/My%20System%20Pages/Console%20IO%20Board/Console%20IO%20Board.htm >> >> ). Because of space I removed the HEX display and a few jumpers. This >> provides direct support for PS2 keyboard and VGA video. Besides the >> internal ribbon cable connectors to the back of a box, I also added IBM-PC >> P2 and VGA sockets at the top of the board for direct connections. Again >> my thinking was KISS. It’s a well proven board totally debugged and is >> completely programmable (currently has VT100 capability as well). I wanted >> to retain the flexible status port and bit configuration jumpers section so >> when sections are disabled to use an external board (see below) the monitor >> need not be. Granted there is a simpler solution such as the PIC32. I may >> have to go to that for space reasons but with the Propeller circuit 99% of >> the work is done it’s just a splice. Also later, the user can get and >> use the Propeller Console IO easier when they build a larger system. The >> interrupt circuit is still there BTW. >> >> >> >> There was an outcry for a serial port. These unfortunately take up board >> real estate badly. I opted to add the (again well proven) USB port chip >> that we used on our Serial I/O board ( >> http://s100computers.com/My%20System%20Pages/Serial%20IO%20Board/Serial%20IO%20Board.htm >> >> ). This 18 pin “chip” takes up little circuit room and actually is easier >> to interface to a PC than a serial port. USB the serial cables are also >> very common. >> >> >> >> Added a few LED’s that’s about it. >> >> >> >> The board has 128K of RAM (there are no common 64Kx8 static RAM DIP >> chips) that can be jumpered into two separate 64K sections. It has a 27C64 >> (or equivalent) ROM, keyboard buzzer, 8 interrupt jumpers, a Power on clear >> and a ROM power on jump to any 1K boundary circuit. I used two, a 5V and >> 3.3V Pololu regulators. There are a lot of chips on this board. A TO-3 >> regulator capable of > 1.5 Amps takes up too much space. Those Pololu >> units are really nice and take little real estate. >> >> >> >> There is a socket to program the Propeller EEROM but the user will have >> to buy the “Propeller Programming Plug”. A serial interface circuit is too >> board space expensive. They would also need to buy a PROM/EEPROM >> programmer (e.g. Wellon VP-290). After that they should have a board that >> would light up an empty S100 bus card cage. Clearly the next thing to do >> would be to build a FDC board or IDE/CF Card board and then go from >> there… >> >> >> >> The circuits are configured so the onboard RAM, ROM, Console I/O and >> serial sections can be inactivated in stages as discrete more functional >> boards are added. While the board will act as a master/slave S100 board >> it’s not really intended to function is a complex multiprocessor >> configuration. For example for debugging you cannot “see” beyond 64K of RAM >> in the bus. >> >> >> >> A few of you wanted more options including a CF card etc. Unless we went >> with a 4 layer board (more expensive, hard to debug), there is >> unfortunately not enough room. GAL’s (or a CPLD) would help but I wanted >> to simplify the board for first time users. The current 74LSxx board is >> amenable to simple logic probe debugging in all the circuits. >> >> >> >> Now the bad news. This board is very dense. The initial via count is >> ~1200 vias! (More in fact than my current 80486 CPU prototype boards). >> It’s taxing Freerouter to find a solution. I playing around with chip >> layouts. May need some volunteers to shuffle things around an try for a >> solution. The multiple jumper options really soak up vias. >> >> >> >> Anyway stay tuned. >> >> >> >> John >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> >> *From:* [email protected] [mailto:[email protected]] *On >> Behalf Of *Richard Cini >> *Sent:* Friday, September 11, 2015 3:09 AM >> *To:* [email protected] >> *Subject:* Re: [N8VEM-S100:7551] Re: A new Z80 based SBC to get >> beginners started on the S100 bus >> >> >> >> On Phillippe's second point, the DSKY already exists for the N8 ECB >> platform so maybe you can reuse that? >> >> >> >> I forget -- would the proposed board have a parallel port or two? That'd >> be great for a parallel ascii keyboard. >> >> Sent from my iPhone >> >> >> On Sep 11, 2015, at 1:51 AM, Philippe Elie <[email protected]> wrote: >> >> Hi all, >> >> >> >> I'm jumping in this thread a bit late, it's a great idea John! I was >> considering building a Zeta SBC but was missing the S100 compatibility. The >> board you suggest could be used not only for diagnostic but also to build a >> compact S100 system based on a 4-slot backplane for example. >> >> >> >> a couple of comments : >> >> - also agree that serial is essential, video not that much. Propeller is >> great but, having spent quite some time tweaking the code, there are >> inherent limitations when running DOS as several programs are addressing >> the video memory directly and this makes it quite difficult to emulate. as >> such, we should rather leave the video chip decision to the user and >> integrate the serial port only. >> >> - I own several old school SBCs, as I guess several people here, KIM1, >> SYM1, TM990 etc and one feature they all have which is neat is a tiny hex >> keyboard and LED digits. I was wondering if this very limited entry/display >> device would also be included in the board, probably via a dedicated >> connector and external daughter board.. that would make debugging, >> patching, etc quite straightforward, and helping in situations where an >> external serial terminal cannot be used >> >> >> >> my 0.002 cents ! >> >> Philippe >> >> -- >> 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. >> >> -- >> 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. >> >
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