[Tip] Switch the Omega to VERBOSE

fossette

So, your Omega(2(+)) doesn't work? What to do? This little piece, shielded by a metal plate may seem like a mystery, an impenetrable black box. Don't let that overwhelm you. The Omega is a little verbose devil... if you know how to listen. And do listen to it! You'll be rewarded with countless hours of spared debugging time.

If you are new to the Omega, go read the docs here:
https://docs.onion.io/
If you have problems with the Omega, go read the guidelines here:
https://community.onion.io/topic/787/guidelines-for-posting-issues-please-read-first
Don't be lazy! Don't be full of yourself! Don't skip it!

But first, something not (yet) mentioned in the docs, ground yourself and perform a thorough visual inspection of all hardware pieces that you receive. Look for non-aesthetic solder blob on the board. I personally found some. Pin solder weren't touching but they were too close for comfort, IMO. To fix that, I used a soldering iron with the pin over the heated tip of the iron to let gravity fix the solder blob. Also, perform this basic test to see if you have any short circuit between ground pins, power pins and the other pins. Statistics from my purchase, 33% of the Omega2+ were affected by solder blobs. I wouldn't say 'sloppy', but it's definitely disappointing. As, is there anything else wrong with those Omega2+?

So now, do you feel your Omega reaching out to you? Great! You are in the right state of mind. The secret is: get connected to the Omega's first serial port (labeled RX0 and TX0). By default, the port speed is 115200 baud. I use this command under FreeBSD:
cu -l cuaU0 -s 115200
Linux, Mac and Windows have their equivalent too.

You bought the Omega without a dock? Well, you know what you are doing, and you are good at it too. Read the docs for the relevant pins, and get connected. You purchased an Expansion Dock? Great minds think alike. It's the easiest way to communicate. You just need a mini-usb cable from the dock to your computer, and those cables are just laying around you doing nothing anyway. You got the Mini Dock instead? No problem! Its mini-usb connector provides the same communication functionality. I can't blame you to like things small. I do too!

If you have the other docks, tough luck, but do not despair. I'm promoting you to EXPERT LEVEL. The first Omega serial port is still available, but you'll need to solder three wires on it (RX0, TX0 and GND). Refer to the docs for the right pin numbers. Remember that it's a 3.3V level. You can build yourself a serial-to-usb circuit of your own, a RS-232 driver, or whatever you like, but do use the first Omega serial port. If not, it's just like driving blind. How long can you last?

William Scott

@fossette Very well written!

I have a serious serial I/O problem that has me baffled. I just picked up on a tidbit in your final paragraph. In reference to the first Omega serial port it is at a 3.3V level. That is no surprise as the device runs at 3.3V. However, this may be at the core of my problem.

I'm getting garbage from the device over the serial port. In the first case I used a breadboard expansion to a serial-to-USB converter. I highly suspect the Omega could not drive the converter adequately as the breadboard signals are true device signals, and the converter was overdriving the Omega serial receiver. On the Omega I connected to both serial ports with the same effect, to no surprise.

In the second example, garbage abounds as well. However an expansion dock is in use and is powered up by 5V only being connected to Tx1 and Rx1. Bi-directional garbage. Is this interface also at 3.3V?

I'd appreciate a reply. FYI, here are my next steps. Somewhere, somewhere, somewhere in the docs find what these interfaces are spec'd at. Put a scope on the Tx1 port to check signal level and quality.

Here's another data point which points to a drive level issue. In one test config I have a sensor device driving the Omega Rx1 twice a second with perhaps 60 characters each message. Only a small percentage of the characters get through at random times, and are unrecognizable.

thanks!
--Bill