April 26, 2022

Sun 3/80

I have the board set from one of these and hope to play with it someday. One board is the video board, which I will almost certainly never use. The other has the CPU, memory, network, and IO.

Two things make it particularly interesting. First, it uses the MC68030 cpu. Second, it is one of the last m68k machines Sun ever made.

From the hardware FAQ: 
Processor(s):   68030 @ 20MHz, 68882 @ 20 or 40MHz, 68030 on-chip MMU,
			3 MIPS, 0.16 MFLOPS
        CPU:            501-1401/1650
        Chassis type:   square pizza box
        Bus:            P4 connector (not same as P4 on 3/60)
        Memory:         16M or 40M physical, 4G virtual, 100ns cycle
        Notes:          Similar packaging to SparcStation 1. Parallel
                        port, SCSI port, AUI Ethernet, 1.44M 3.5" floppy
                        (720K on early units?). No onboard framebuffer.
                        Code-named "Hydra". Type-4 keyboard and Sun-4 mouse,
                        plugged together and into the machine with a small
                        DIN plug. Boot ROM versions 3.0.2 and later allow
                        using 4M SIMMs in some slots for up to 40M.

Click on the image below for a really big image of the board. What you will get is bigger than you may think (3840x3125), but will probably be resized to fit your browser.
You know what you need to do if you need or want to see it full size.

The board is 10.5 by 9 inches in size and weighs just under 2 pounds (without the framebuffer board attached). Mine (the one shown) has 16M of ram in place, four 4M SIMM modules.

Some of the big items on the board are:

The connectors on the back panel are:

Disks

On the board (inside) is a 34 pin connector (no doubt a floppy).
Also there are two 50 pin SCSI connectors with power connectors nearby.

Memory

As for memory, you could load it up with 16 modules of 1M each. That is the simplest thing to explain.

Place the board with the connectors towards you.
(As in the photo above)
This will cause the memory slots to lean towards you.
You have 8 on the right and 8 on the left.
Let's number then from 1 in the back (away from us) and 8 in the front (near us).

To install 4M of ram you put 4 ram sticks into slots 1 and 5 on both left and right.
To install 8M of ram you put 8 ram sticks into slots 1, 3, 5, and 7 on the left and right.

You can use 4M modules, but apparently only in the first two banks.
What is a bank? We have 4 banks.

If we load 4M modules into banks 0 and 1, then 1M modules into banks 2 and 3, we get 4*8 + 8 =32 +8 = 40M.

I have a bunch of RAM modules that were stored in the box with my Sun 3/80.
Some of them have only 8 (or 2) chips. These don't have parity and won't work.
The rest have either 9 or 3 chips. These have parity and will work.

I spent some time searching RAM part numbers to figure out what I have. It seems that 70 ns speed devices are recommended for the 3/80.
Modules with 3 chips are usually two 4 bit wide devices along with a third device that is one bit wide for parity.

Jumpers

I describe the jumpers as they actually are on my board: 
J1000	1-2	OUT	Watchdog reset(test)

J020	1-2	IN	68882 20MHz
        2-3	OUT	68882 40MHz

J043	2-3	IN	RS232C (-12V)
J043	1-2	OUT	RS423 (-5V)

J044	2-3	IN	RS232C (-12V)
J044	1-2	OUT	RS423 (-5V)
I don't see myself needing or wanting to change any of these jumpers.

Sad to say, there is no reset button as on other Sun3 boards.
There is no Diag/Normal switch either.

The NVRAM

You can do some surgery on the NVRAM and remove the dead battery bonded on top. This exposes two metal strips. One is ground (it goes to pin 12?) Figure out a way to connect a new 3V lithium battery. Perhaps a coin cell in a socket!

Connect a serial terminal to port a (25 pin) 9600 baud, 8 bits, no parity. L1-A on a real keyboard gets you to the PROM. Once there, see these notes.

Feedback? Questions? Drop me a line!

Tom's Computer Info / tom@mmto.org