Mac se30 GPIO ?

[daveosx]

I have a pretty good command of the beagle bone black and use it extensively for projects.

I started programing back in the late 1980s using Mac Rail and Nubus cards each with 50 addressable GPIO.

I also have three of the Buzzz ADB I/O devices I used back in the 90s for home automation.

RealBasic has been a friend for a really long time.

SO what I am wondering is if there is any exposed GPIO on an SE30 or some unused GPIO on the PDS slot ?

I have a couple of things in mind one is a video card for grey scale and HDMI out using a BBB.

The other is possibly implementing SPI or I2C off the PDS slot.

Either I think would be popular hacks for the community.

Let me know if any of you have had a similar idea about the GPIO.

 

[mrpippy]

I've had fun in the past looking for old university courses that used Macs (particularly 68k assembly).

I found an old physics course at UC Davis where the labs used 68k assembly to directly write to SCSI chip registers to treat the SCSI data lines as GPIOs. This was on a Mac SE booted from floppy though, no other SCSI devices on the bus would be happy!

Physics 116B Lab 17: Microcomputer I/O Projects With the SCSI Port

There's also some Intro to 68k slides:

http://physics.ucdavis.edu/classes/Physics116/P116B_notes/M68000a%20Intro.pdf

http://physics.ucdavis.edu/classes/Physics116/P116B_notes/M68000%20Intro%20II.pdf

http://physics.ucdavis.edu/classes/Physics116/P116B_notes/M68000%20Intro%20III.pdf

and notes on 68k assembly:

http://physics.ucdavis.edu/classes/Physics116/expt_17notes.pdf

A lot of these courses used MAS, the "Macintosh Assembly System" which was a textbook and some kind of software/assembler, info about it on the internet is rare.

 

[paws]

The PDS slot is basically the memory and address lines drawn out. A card with some latches could give you something like GPIO and would be fairly simple for someone with some understanding of digital electronics to do. I have no idea about the software side of it, though.

SCSI and Nubus would be more involved.

 

[bigmessowires]

You could also build an ADB-based GPIO expander. Then it would work on basically any Mac.

 

[olePigeon]

I wonder if that's how the various companies made SCSI to Video adapters and SCSI monitors?

 

[rsolberg]

ADB is intriguing, but I wonder if its limited bandwidth could be an issue. It has a ground, two +5v lines, and only one signal line, without a clock. Apple's RS-422 serial port implementation seems pretty robust, particularly compared to common RS-232 ports on PCs of the era. Perhaps a serial to TTL transceiver would do the trick? I just used a MCP23008 via i2c on my Raspberry Pi to create an external GPIO breakout, if one could get from serial to i2c or SPI, such an IC would give you multiple GPIO pins from just signal and clock.

 

[daveosx]

You could also build an ADB-based GPIO expander. Then it would work on basically any Mac.

There was a european company that produced a ADB IO unit called Buzz from beehive technologies I have three of them.

Many years ago I built a home automation system that used the 6100 voice recognition and applescript with an OSAX to trigger events.

Later I built a ELO touch screen and used real basic to make a panel in the hall.

I replaced that about three years ago with a BBB and I use an iPad or iPhone as the controller interface.

 

[daveosx]

I've had fun in the past looking for old university courses that used Macs (particularly 68k assembly).

I found an old physics course at UC Davis where the labs used 68k assembly to directly write to SCSI chip registers to treat the SCSI data lines as GPIOs. This was on a Mac SE booted from floppy though, no other SCSI devices on the bus would be happy!

Physics 116B Lab 17: Microcomputer I/O Projects With the SCSI Port

There's also some Intro to 68k slides:

http://physics.ucdavis.edu/classes/Physics116/P116B_notes/M68000a%20Intro.pdf

http://physics.ucdavis.edu/classes/Physics116/P116B_notes/M68000%20Intro%20II.pdf

http://physics.ucdavis.edu/classes/Physics116/P116B_notes/M68000%20Intro%20III.pdf

and notes on 68k assembly:

http://physics.ucdavis.edu/classes/Physics116/expt_17notes.pdf

A lot of these courses used MAS, the "Macintosh Assembly System" which was a textbook and some kind of software/assembler, info about it on the internet is rare.

Wow thanks cool slides 

Instantly added to my library

I wrote a bit bang for a parallel port to control some IO on a disc chasing ripper I built 

never thought of using the scsi the same way cool.

 

[daveosx]

The PDS slot is basically the memory and address lines drawn out. A card with some latches could give you something like GPIO and would be fairly simple for someone with some understanding of digital electronics to do. I have no idea about the software side of it, though.

SCSI and Nubus would be more involved.

Yep what I am thinking

SO if I could find some group of unused address space  

in theory I could just read/write some bytes to those addresses to produce io

The serial interface is real simple.

 

[daveosx]

Apple's RS-422 serial port implementation seems pretty robust, particularly compared to common RS-232 ports on PCs of the era. 

Yep at motorola I used some cherry semiconductor shift registers to produce IO

On Autovision 90 controlled RT3200 series robot arms some place I have the notes on the chip numbers.

But what I am really wanting to do is feed video out to a BBB and convert to grey scale out use a diy grey scale adapter to produce grey on the internal monitor , also maybe make a 68040 emulator on the BBB the same way and possibly use the HDMI out as an external monitor.

So I am thinking i could design a cape and overlay that would enable the BBB to take the place of a Dimo 040, an Xceed and a Danya port plus allow USB connectivity.

The form factor would be PDS on one end and a bracket to allow the USB Ethernet and HDMI out through the access slot on the back.

Sort of a king of the mac upgrade for the Se30.

 

[techknight]

Look at the developer notes, there is a ton of unused addressing available, As well as slot space. 

 

[Bunsen]

You may be interested in this project:

http://synack.net/~bbraun/sevideo/

Development thread -
https://mac68k.info/forums/thread.jspa?threadID=276&tstart=0