best way to add the back plane connections?

[John Galt]

What is the best way to Add the 25 connections to the DUE?

are most without the newer main boards just soldering directly to the DUE?

do i have to worry about electrical noise and shielding?

just wondering how others have done it.

Thank you

[John Kennedy]

I soldered wires directly to the Duo in order to interface with the floppy interface. 

I do NOT recommend this approach. 

It worked but it’s a fragile mess. 

I *think* someone made a PCB daughterboard that broke out all the connections. That would be smart. Maybe Adwaterandstir could make something similar for those of us without the systems that have  the connection already onboard?

[John Galt]

i was also worried about replacing the DUE in the future if the need came up and having to resolder everything.

I thought about soldering to the front but that seems a larger mess.

i'm waiting for the new reproduction case and any new PCBS that David makes with the Back plane so i didn't want to start changing out boards on something temporary.

well temporary but not really.

i plan to have the backplane external and connect everything via a short shielded 25 to 25 pin connector.

[Brian Welland]

Hi all,

This is the gerber file for a suitable PCB as suggested above.

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[Patrick Jackson]

Thanks a ton for the gerber! I'll send this out, and work on a new internal cable. My method of direct soldering has completely failed XD

[John Galt]

Now I can see why people had a hell of a time soldering connections to the due board.

It took me a few hours to make a nice easy to read layout of where to solder the wires as the 8 data lines are not straight forward on the DUE

Also deciding if I should add a power switch to the backplane separately.

[John Kennedy]

Hi - do you have a photo of the breakout PCB attached to an Arduino?

I have ordered some boards from your gerber files, thank you!

[John Galt]

the side with the outline in white gets the DUE plugged in and the 25pin connector. the other side that is blank goes to the front panel board.

it has to because the 25BD connector has to stick out and point backward away from the front panel so you can plug into it with the DUE next to it.

i don't know what pass through connectors are required. i decided to solder to the DUE pins, since it would be another few weeks of getting the pcb made and then sourcing all the components.

the breakout PCB helped me understand what pins i needed to use, as it is very confusing without really laying out where things go.

[John Kennedy]

Yeah took me two goes to get all the right pins soldered. 

It looks so bad I’m having make the PCB to avoid the shame. 

[John Galt]

mine will be hidden inside the main case, i made an external case for the backplane. I already modified my DUE with a bunch of other external wires, figured oh well.

I put the LED Output Register card in the first slot so i could show output from the front panel 
the disk controller has side USB port access.

[John Kennedy]

I got my PCBs back to add a 26 way connector to the system, but I must admit I can't immediately see how to use the board with the existing arrangement of pins and sockets.

A photograph of the PCB in a working system would be very helpful!

[John Galt]

in order to use that pcb you have to source a bunch of the pass through connectors.

i felt it was not going to go well so i went with the direct method of soldering a ribbon cable to 25 pin.
the 26th pin is not used, its listed as just ground but its left open.

the printed side with the white text is where the DUE is plugged in. the black back side goes to the Altair front panel PCB.

the white 26 pin is where the 25 db connector goes in and sticks out the back towards the DUE

here is a PDF i made of the pin outs and where they go on the DUE. 

soldering all 25 connections to the DUE was tedious but it only took a few hours working in stages, i did the misc wires first then grouped the Data connections and then the address connections.

[John Galt]

oh i also took 3.3V, 5.0V, VIN(RAW) and Ground from the main Altair PCB panel on the right hand side for convenience and power connection ease.

[John Kennedy]

Hmm. Looks lIke the 26 pin connector will block access to the USB and power inputs. Would have been better if the connector was on the other side, or at the top or bottom. 

[John Galt]

Depends on the height of the pass through connectors, issue for me is I can’t get components, I figured after I ordered the pcb then I would spend weeks trying to find the right connectors verse just spending a few hours soldering and then I could route everything myself.  I also felt the 25 db pin was too close, some people instead of putting the 25db there have a 25db on a ribbon cable and solder the ribbon cable into that spot to make clearance run the 25db out the back panel. 

[John Kennedy]

I built the breakout board, and the AltarDuino is still wokrking!

Before I test it with the disk interface card I need to confirm the ribbon cable orientation. 

Q. There is a jumper on the breakout board. What’s the purpose? Open or closed for floppy interface?

[John Galt]

I believe that 2 pin is for a power input I traced it 2 weeks ago but forgot exactly where it hooks up.

I remember one side was ground and I think the other went to raw voltage.

Don’t propagate those 2 pins and don’t use them. 
 

The have regulation on the aurdino side and the backplane side already.

[John Galt]

Also now is the time to install the Rx/Tx modification on the due.

For another serial port.

Use 3.3v for that new serial not 5v learned that.

Then you wire in a 9db pin converter board and

Flash the firmware for the new port and enjoy I use mine for the fabgl ansi terminal as primary

Which is a better vt100 terminal with 64 colors and more graphics capabilities over the Geoff terminal.

[John Kennedy]

I need to get everything working first.. after transitioning from the rats nest of wires to the PCB, everything has stopped working. Two of the pins in the central cluster of six accidentally got shoved into the same socket, and I had to refresh the Arduino to get it working.

The disk drive controller card seems completely dead, and I can't even get 5v to 3.3v at the IC sockets on that card. That was my weekend.

[John Galt]

ouch.

:(

[Patrick Jackson]

John Galt, are you saying that there's another terminal firmware for the included terminal board that has more features than the default setup?

Also, I removed the ratsnest I had for the gpio breakout and I instead installed one of the PCBs that break out the 25 lines.

However, I get the exact same behavior has before, even after double and triple checking my wiring! I get random LEDs on the main Altair board turning on/dimming and I get hot chips on the led register board!

[Patrick Jackson]

Also, its this version of led card:
https://adwaterandstir.com/product/led-output-register/

[Patrick Jackson]

The only chip that I slot into the led register board that DOESN'T cause problems is the 74HC00 chip in the top left. Adding any other chip causes some LEDs to turn on, dim, or turn on only when certain addresses are selected.

[John Kennedy]

Is your Duo flashed with a build of the Altair firmware that includes IO support?

[John Kennedy]

yes, the designer of the board confirmed that those pins are not a jumper but a location for external power.

[John Kennedy]

Very ouch. I've ordered one of the LED IO boards, just to confirm that the breakout board is working. If that's all good, I will either continue diagnosing the floppy driver or get a replacement.

[John Galt]

There is a fixed version for the Geoff Terminal that i put out.

the Geoff Terminals Graphics modes do not have a function to erase one element at a time.

So for example If you draw a pixel you have to clear the entire screen to remove it which is very slow.

I added additional escape codes so you could

   

place a pixel, erase a pixel

place a circle, erase a circle

place a circle fill, erase a circle fill

place a box, erase a box

place a box fill, erase a box fill.

 

Draw a line ESC [Z1;;;;Z 

Draw a box ESC [Z2;;;;Z 

Draw a filled box ESC [Z3;;;;Z 

Draw a circle ESC [Z4;;;Z 

Draw a filled circle ESC [Z5;;;Z   

Erase a line ESC [Z6;;;;Z 

Erase a box ESC [Z7;;;;Z 

Erase a filled box ESC [Z8;;;;Z 

Erase a circle ESC [Z9;;;Z 

Erase a filled circle ESC [Z10;;;Z   

if you have the patch on your terminal it will show my name as a john galt graphics patch on start up.

The problem with the Geoff terminal is VT-100 support is terrible.

the board included with the pro also supports the SD card and the serial port so you want to keep them.

a much better terminal exists in the FABGL VGA32 Ansi Terminal which also has full VT-100 support in addition it supports many other vintage terminals.

the terminal also supports 64 colors characters and graphics including Sprite and sound support.

in order to use it you need to use up a Serial port, the stock Altairduino pro comes with one 9pin Serial port. the USB ports provided are slave ports.

in order to really use them with external devices outside of a laptop or desk top you have to construct a USB server to 9DB, which i did create, however its not perfect and has issues with many usb devices.

the best solution is to Hack the DUE main board and install another serial port using the TX and RX Leds, then wire up ground and 3.3V power to a 9DB converter, update the Firmeware to support the new serial port

you will then have two 9DB serial ports you can map how you like. i installed the FABGL Ansi Terminal on the new second 9DB serial port and mapped it as primary.

now i have color and graphics support along with full VT-100 escape code support. this allows me me to view color pictures on my Altair and go to BBS over my Wifi modem and see the ASCII Art in color.

i can also view HTML websites and see color pictures through IMP 2.45.

I stopped using my Geoff terminal about 3 years ago now.

[John Galt]

====

Also, I removed the ratsnest I had for the gpio breakout and I instead installed one of the PCBs that break out the 25 lines.

However, I get the exact same behavior has before, even after double and triple checking my wiring! I get random LEDs on the main Altair board turning on/dimming and I get hot chips on the led register board!

====

it is possible your DUE was damaged when your wiring was a little off from before.

would have to swap in a known good DUE and see if the behavior is the same. 

start working from there, as you could still have wiring issues somewhere.

in order to keep myself organized i used a 25DB break out board with all the pins labeled for me.

i then double checked continuity between all due and 25DB pins.

the DUE pins will all read continuity which is annoying but you can still check you have the correct wire from the DUE going to the correct DB25 pin.

I also 3d printed a bunch of things for my PRO case to make sure everything was organized 

and i created an external Backplane box with the led registers visible from the front. i can program it as a display as well.

[John Galt]

i wrote a little basic program that blinks the LED registers as a test i used it as a first test to make sure everything was wired correctly.

i can post it later.

[Patrick Jackson]

Thanks for the input (heh)!

I'll swap out the Due, I got a few kicking around...

Also, one of the chips gets super hot, which is a bit upsetting. I may have killed it when I did a direct solder job. I also wonder about the flux messing things up, but I'll do a new Due just in case.

I'll also take a look at the terminal update and a fabGL board! Looks absolutely INCREDIBLE, jpgs on an Altair! (well....kinda XD )

I'll mess around with it tonight

[John Galt]

you might also suspect something is wrong with the LED register card. if you pull it out and a chip on the DUE is still hot then you could suspect the DUE if the chip is colder then could be something on that card.

you could run continuity checks on each line on the backplane to see if something is shorted.

Flux can cause shorts its a good idea so scrub down the flux with IPA and rule it out. 

inspect your boards for extra solder that went flying during your work. a random blob could have fell into a board and caused a short.

i should start using my GITHUB... i posted my version of the PPMVIEWer with dithering support and printer support for Okidata printers.

i stopped working on it 2 years ago because i got side tracked by too many projects.

for the information on viewing HTML

https://github.com/johngalt01/johngalt01.github.io

https://forum.vcfed.org/index.php?threads/viewing-html-on-a-s-100-machine-with-pictures.1245743/

[John Galt]

if you want to roll the lights on the leg register card

10 ' MAKE THE FRONT LIGHTS BLINK
20 '1,2,4,8,16,32,64,128
30 WHILE INKEY$=""
40 OUT 255,1:GOSUB 300
50 OUT 255,2:GOSUB 300
60 OUT 255,4:GOSUB 300
70 OUT 255,8:GOSUB 300
80 OUT 255,16:GOSUB 300
90 OUT 255,32:GOSUB 300
100 OUT 255,64:GOSUB 300
110 OUT 255,128:GOSUB 300
120 WEND
125 OUT 255,0
130 END

[Walt Perko]

Hi, 

I posted a few BASIC programs to do different designs with the LEDs on the expansion backplane LED board.  

http://www.brainless.org/Altair/Repository.html#section4

.

[Patrick Jackson]

Ah, the Due chip doesn't get hot, its the chip below the nand gate that gets hot

[John Galt]

Check inside the P1 connector to make sure no solder blobs got in there.

[Patrick Jackson]

I may need to get a few more of those chips. The solder all looks clean. Everything else works when that card isn't plugged in!

I'll try flashing the due with the io software again. Pretty sure I already did...

[Patrick Jackson]

Same behavior. Let me try to clean the flux again.
Are we sure the Due is bad? It works 100% every other way, leds, sd card, serial ports

[John Galt]

 if everything works except the led register card then it has to be something on that card.

or something conflicting with the card.

If you pull all the cards out of the backplane and just use the LED register card alone, does it have the same issues?

[John Galt]

    74HC04 or MC74HC273A could have been damaged. those use address lines and Data lines. if chip blew internally then it could be selecting more then one LED and that is showing as dim lights and trying to light more then one at the same time.

[Patrick Jackson]

Yeah, I only have the LED r