Connecting Mac to Altair-Duino via USB

[Greg Lovekamp]

I have the simplest question in the world: how can I use my Mac to connect to my Altair-Duino via USB? I have followed what I have found online.

• Connect cable.
  
• From terminal, determine /dev entry; appears to be /dev/tty.usbmodemXXXX (it comes and goes with cable being connected/unconnected and XXXX changes when doing so
  
• Use “screen” command: screen /dev/tty.usbmodemXXXX 115200

I’m supposed to see some message, but I get nothing. If I use switches to load and run BASIC on Altair-Duino, LEDs flash as expected, but I get nothing on my Mac. For the world, it just looks like my Mac doesn’t behave as other’s do, and I have no connection.

What am I doing wrong? This is truly the simplest of things, but I can’t get it to work!

[Chris Davis]

I just tried it and it works great:

From Terminal I entered "screen /dev/cu.usbmodem14101" and it worked.  If I tried to include a baud rate it did not work.

I normally use Serial2 and it's super easy

[Chris Davis]

Oh yeah, John is correct.  The default baud rate is 9600, so "screen /dev/cu.usbmodem14101 9600" works.

[Chris Davis]

Sorry, I was assuming you were connecting to the Altair-Duino 680 (which has a default baud rate of 9600).  The Altair-Duino 8800 has a default baud rate of 115200 at the programming port of the Arduino.

Make sure you are connecting to the programming port (not the native port).  It is the USB connector closest to the Arduino power jack.

If you're absolutely sure you're connecting to the programming port, try using Serial2 (it has a free 30 day trial) or CoolTerm.

[Tom Wilson]

Isn't there also a magic power up switch combo to pick the Native USB port profile? If not, is that the default if you remove the configuration files from the SD card? 

[Chris Davis]

By default there is not a configuration to use the native USB port, but it would be easy to add one.  Unfortunately you'd first need to use a serial device of some sort to create that configuration.

The default with no configuration loaded is to use the programming USB port.

[Greg Lovekamp]

I only have ONE USB port…

[Chris Davis]

Look where you connected that USB extension to the Arduino.

[Chris Davis]

I checked your order and I see you purchased an assembled and tested unit.  So it is connected to the Programming port (unless something changed in the past five years).

Have you used this since you bought it?  Do you have another computer you can connect it to?  Does it otherwise power up when your connect it via USB?

[Greg Lovekamp]

Ah, THAT explains it. I have used the Altair-Duino, but I have always used it connected to my home network, then I’ve used telnet to access it. I have never used it connected to USB.

I was going to take it to our local vintage club meeting; we have some actual vintage machines and some replicas. So, I’ve been trying to configure it for travel where I won’t have my network. Along the way, I found an interesting shell that has jitter, screen burn in and such, and I thought “wow, that’s so much better!” So, I figured I’d skip the network all the time just for the “feel”. Oh, well.

[Tom Wilson]

It's easy enough to change. Hold Stop + Aux1 Up to access the main menu, then configure the serial port to use USB. 

Save your network setup as Preset 1 and the USB setup as Preset 2. Then you can switch between them at boot by setting the front panel switch to (right switch for network, second switch for USB) and holding DEPOSIT when you power up the Altair.

I also turn on Serial Console and Serial Input in the menu, so I can immediately see that a boot message to confirm the desired port is working. (Also, so I can use the Altair from across the room.)

[Chris Davis]

How did you select the wifi modem as the input/output device?  The default may be set up to use pins 18/19 instead of the USB port.  I would raise STOP+AUX1, reset to defaults, and save the configuration as #0.  Then when you connect to the Altair-Duino via USB it should work. 

[Greg Lovekamp]

I have no idea how I originally configured things; I'm guessing it came that way? If I set data to be 000001, and hold DEPOSIT up while switching on, it will allow Wi-Fi input. NOTHING I do seems to get me USB access from my MacBook; i.e., no switch setting upon power-on seems to do it. While telnetting across wi-fi, I can get the configuration menu by STOP-RESET, but I cannot the type anything to actually perform any configuration.

I am sure this is something really simple, but I need to be told like I am a complete imbecile the steps to fix it. Obviously, I am hesitant to clear wi-fi settings (as if I could) since that is the ONLY access I get to this box.

Am I able to perform the configuration using switches on the panel since I cannot get communication to occur when in configuration.

[Greg Lovekamp]

Is it as simple as needing some special Mac driver? As I say, consider me REALLY stupid.

[Chris Davis]

Remove the SD card.  It will revert to default settings (which is to use the USB programming port).

If that works, then download the SD card files and copy them to a new SD card: https://adwaterandstir.com/instructions/

[Greg Lovekamp]

SOLUTION: The internal extension was connected to the Native port rather than the Programming port.

I took it apart. Disconnected the extension, and tried connecting to the  port it was plugged into. No good. Then I noticed the other port, noticed the labelling, and thought "hey, I remember this Native/Programming port thing". I reread the messages in this thread, and got the gist that I should be plugged into the Programming port. I plugged my MacBook into the Programming port and it worked like a charm. I plugged the extension into the Programming port, reassembled everything, and it all works perfectly!

If I set 001 and hold DEPOSIT when powering up, I can connect through wi-fi. If I don't hold DEPOSIT up, I can connect to USB.

I am VERY happy, albeit a little slow on the uptake. Thank you for all the help.