Trill Square initialization issues

felixmurray

I recently bought a Teensy LC to use with Trill Square, handling USB MIDI data. The Teensy section of the getting started documentation is useful - however, when I plug Trill Square into the 3.3V, GND and SDA/SCL pins (18/19), I get this error message:

failed to initialise trillSensor
Error code: 2

The Trill.cpp script looks like it returns error code 2 when it fails to identify the connected device, although I'm not sure. Is this an issue with my hardware connection? Is it something to do with the I2C bus setup?

giuliomoro

It will work powered at 3.3V. According to our docs, on the Teensy LC you need to use pin 18 for SDA and pin 19 for SCL and add separate 2k2 pullups from each of these to 3.3V. I am not 100% we verified this on an actual device though. Also, the Trill needs to be powered up about 300ms before your board tries to read from it.

felixmurray

Currently I am using 4k7 pullups, but I'll try 2k2 as well. Adding a delay of 500ms after the setup block doesn't change anything, unfortunately. What does error code 2 refer to specifically? This happens on my own code, but also using the square-print example.

I know the Trill library uses the first I2C bus (pins 18 & 19), but is there a way to override this and test using the second I2C bus on the Teensy LC? This would make sure I haven't fried those pins somehow.

giuliomoro

felixmurray Currently I am using 4k7 pullups

That's fine... no need to switch to 2k2

felixmurray What does error code 2 refer to specifically?

It means that identify() failed https://github.com/BelaPlatform/Trill-Arduino/blob/master/Trill.cpp#L49 , namely , it is Wire.requestFrom(i2c_address_, (uint8_t)3); which returned fewer than 2 bytes
https://github.com/BelaPlatform/Trill-Arduino/blob/master/Trill.cpp#L97 .
That would most likely mean that the I2C device at the given address didn't respond. This could be a wiring issue, wrong device address or an issue with the Trill itself.

felixmurray I know the Trill library uses the first I2C bus (pins 18 & 19), but is there a way to override this and test using the second I2C bus on the Teensy LC? This would make sure I haven't fried those pins somehow.

It's not actually straightforward to do that, because Wire. However, it is also possible that we got our documentation wrong - as it seems that we didn't actually test with the LC, so it's worth trying the alternative I2C pins and see if our docs is wrong.

giuliomoro

it seems there may be some underlying issues ...

Are you using Teensyduino?

This thread may be of help. Running the I2C scanner could also help identifying any pin/connection issues
https://forum.pjrc.com/threads/58779-Teensy-LC-I2C-communication-issues

It seems that possibly one needs to use Wire.receive() instead of Wire.read() in the Trill.cpp file. We are getting a Teensy LC to test this, but it may take a week before we get around to it, so you may want to try a few of these things on your own.

felixmurray

giuliomoro yeah, I'm using Teensyduino.

I think for my setup it may have been hardware connection issues - I made sure the Trill sensor was working by checking my code with it connected to an Arduino MKR 1010 WIFI, then returned to the Teensy LC and started to get intermittent successes. When everything's hard soldered up I'm hoping most of these issues go away - it seems breadboard connections don't really cut it for this kind of thing.

Thanks for the help! It will be interesting to see if using Wire.receive() makes any improvements.

giuliomoro

Hmm that's interesting ... I never had troubles with breadboards and Trills, but every breadboard is worn out in a different way!

giuliomoro

It seems that it works just fine with Teensy LC https://madskjeldgaard.dk/posts/multi-touch-trill-controller1/ https://github.com/madskjeldgaard/trillbar-teensy-lc-controller/blob/main/src/main.cpp