NOVA 445

Description

System Requirements:
1. Emulate Data General NOVA computer
2. Use Fairchild F9445 microprocessor
3. Include provision for switch-and-light front panel
4. Include provision for ROM-based monitor program/debugger
5. Capable of running Data General's Real Time Disk Operating System (RDOS)
6. Full 32K words (64KB) of RAM available when running loaded code
7. Peripheral support: TTY I/O, Real Time Clock, emulated disk subsystem (minimum 1 drive, preferably more)
8. Include provision for graphic display (min 256x256 pixels)

Files

schematics033120.pdf

Preliminary Graphics processor board schematics (subject to change)

Adobe Portable Document Format - 500.89 kB - 04/01/2020 at 02:23

Preview

Download

RAMTST.LST

Example asm445 listing output (Monitor RAM test)

lst - 3.21 kB - 03/21/2020 at 20:34

Download

asm445.pl

Crufty assembler for NOVA 445 ROM code. Written in Perl, generates .hex files for low & high byte.

pl - 31.22 kB - 03/16/2020 at 01:08

Download

CPU Board Schematics 02222020.pdf

Preliminary CPU board schematics (subject to change)

Adobe Portable Document Format - 778.78 kB - 02/22/2020 at 19:18

Preview

Download

F9445 pamphlet.pdf

1983 Fairchild marketing document for F9445 microprocessor

Adobe Portable Document Format - 12.54 MB - 12/15/2019 at 03:22

Preview

Download

Project Logs

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Video Output
Steve Toner • 2 days ago • 0 comments
Graphics Board
Steve Toner • 05/27/2020 at 01:52 • 0 comments
Bus-Sniffing Debug Stick
Steve Toner • 04/24/2020 at 03:15 • 0 comments
Testing 64K Mode
Steve Toner • 04/17/2020 at 04:37 • 0 comments
PCBs Shipped
Steve Toner • 04/12/2020 at 16:02 • 0 comments

That was fast... PCBs are complete and being shipped by DHL. Come on, DHL! My house isn't that hard to find ;-)
Ordered PCBs
Steve Toner • 04/09/2020 at 17:56 • 0 comments

I ordered PCBs for the video board from JLCPCB yesterday. We'll see how this goes with the current COVID-19 situation. I had to choose DHL as the shipping option, as my preferred option (SF Shipping/UPS) is not currently available. DHL has never been able to find my house, so I avoid using them if possible.
Memory Test & PCB Mod
Steve Toner • 03/21/2020 at 20:31 • 0 comments
Sending Morse Code
Steve Toner • 03/16/2020 at 16:37 • 0 comments

Problem shown in last video turned out to be very simple to find & resolve.
Status Update
Steve Toner • 03/15/2020 at 22:37 • 0 comments
It's Alive!
Steve Toner • 02/21/2020 at 05:11 • 1 comment

First signs of life...

View all 12 project logs

Discussions

Robert Armstrong wrote 02/08/2020 at 22:23

Any updates on this design? I have two F9445 chips myself and would be interested in seeing what you come up with. I'd also love to find a 9470 console chip, if anybody has one!

Are you sure? yes | no

Steve Toner wrote 02/22/2020 at 05:34

Update posted.

I don't know how many of the support chips actually exist. The datasheets that are out there on the web say "Advance Product Information" for the FPP (9443), MMPU (9444), DMC (9446), IOBC (9447), PMI (9448). The F9470 does appear to be an actual part as of the January 1983 Microprocessor Products Data Book. A web search does show www.4starelectronics.com claiming to have 46 9470s (and maybe some F9444s? These may be an 8-pin microcontroller) in stock as of right now...

Are you sure? yes | no

Robert Armstrong wrote 02/22/2020 at 16:01

Thanks for the pointer. I submitted an RFQ for qty 2 F9470s, and I'll post if I get a response. I'm not hopeful, but maybe I'll get lucky. Have you posted a schematic for your Nova 445? I'm not familiar with I2L logic, and I'm interested to see what you did with the Iinject pin. Did you just use a resistor to Vcc, or did you implement a constant current source to drive it? Thanks again.

Are you sure? yes | no

Steve Toner wrote 02/22/2020 at 18:16

I haven't posted the schematics yet. I usually like to wait a while until any major mistakes reveal themselves :-)

I just used a 10 ohm resistor (10W/TO-126 case + heatsink -- you can see it below the CPU socket in the thumbnail for the "Introducing..." video) for the Iinj. I don't think it needs anything fancier than that. One thing about the processor though: a logic '1' output is only about 3.6V. In spec to drive a TTL load, but much lower than what you're probably used to seeing in typical TTL/NMOS/CMOS circuits...

Are you sure? yes | no

Robert Armstrong wrote 02/22/2020 at 18:47

Thanks. It'd be easy enough to construct a constant current source using a 3 terminal linear regulator, but I don't really understand all the trade offs in how this affects the operation of the uP. Good to know that a simple resistor will work.

I was aware of the TTL output levels; I'm planning to use 74HCT or ACT parts for things that are directly driven by the 7445. These are CMOS parts with input thresholds skewed to match bipolar TTL.

Are you sure? yes | no

Steve Toner wrote 02/22/2020 at 19:38

OK, I've posted the current schematics for the CPU Board.
I used a mix of different happy families of chips. Mostly 74F (and U5/U6, though shown in the schematic as AS, are actually F), but some S and LS (had 'em) and the bus transceivers (U8/9, U20/21) are ABT... Then there's a plain old 7406 & 7407 and one ALS part just for good measure (U14, shown in the schematic as an S) Date codes range from 1977 to yesterday :-)

Are you sure? yes | no

Ken Yap wrote 12/15/2019 at 07:19

Great! Looking forward to seeing this bit of computing history come alive again.

Did you happen across the CPU or did you purposely seek it out? I notice that it uses I3L. I2L was described in https://hackaday.io/project/159059-adventures-in-time-integrated-injection-logic

Are you sure? yes | no

Steve Toner wrote 12/15/2019 at 16:12

I sought it out. The DGC Nova was the first computer I used/learned about/programmed, and I actually interviewed at Fairchild back when its predecessor, the F9440, had just been released.

They are quite hard to find these days, but I managed to acquire two...

Are you sure? yes | no

NOVA 445

Description

Files

schematics033120.pdf

RAMTST.LST

asm445.pl

CPU Board Schematics 02222020.pdf

F9445 pamphlet.pdf

Project Logs

Collapse logs

Video Output

Graphics Board

Bus-Sniffing Debug Stick

Testing 64K Mode

PCBs Shipped

Ordered PCBs

Memory Test & PCB Mod

Sending Morse Code

Status Update

It's Alive!

Discussions

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schematics033120.pdf Preliminary Graphics processor board schematics (subject to change) Adobe Portable Document Format - 500.89 kB - 04/01/2020 at 02:23	Preview	Download

RAMTST.LST Example asm445 listing output (Monitor RAM test) lst - 3.21 kB - 03/21/2020 at 20:34		Download
asm445.pl Crufty assembler for NOVA 445 ROM code. Written in Perl, generates .hex files for low & high byte. pl - 31.22 kB - 03/16/2020 at 01:08		Download
CPU Board Schematics 02222020.pdf Preliminary CPU board schematics (subject to change) Adobe Portable Document Format - 778.78 kB - 02/22/2020 at 19:18	Preview	Download

F9445 pamphlet.pdf 1983 Fairchild marketing document for F9445 microprocessor Adobe Portable Document Format - 12.54 MB - 12/15/2019 at 03:22	Preview	Download

NOVA 445

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