Alphanumeric Display with RedBoard Turbo not working

Components & Accessories Displays
1

Hi, i am trying to use a SparkFun Qwiic Alphanumeric Display with a Readboard Turbo and a Qwiic 500mm cable but is not working, library gives all the time “Device did not acknowledge”. Tried different addresses and different displays (we purchased 4) and none of them is connecting. The board and the cable is working ok with a Sparkfun Twist rotary.

2

Try cutting the i2c resistor traces pictured under the heading “I2C Bus Resistor Jumper” here https://learn.sparkfun.com/tutorials/sp … e-overview to disable the pull-up resistors (these can always be re-activated by placing a solder blob between the pads later if needed)

Any luck?

3

I’m going to try this now, but as an update, i tried the displays in a Mkr zero wifi 101 and they work as expected…

thanks

4

I can’t make it work on the RedBoard Turbo, i even tried putting very short cables, pull-up or not… and in the arduino Mkr family they work ok, i can daisy chain 3 with 500mm cables and i suspect for the 4th one is only a matter of cable lenght. So i think it could be a bug in the sparkfun samd21 core and/or the display library

5

Where are you connecting sda and scl?

6

In the Redboard turbo tried using qwiic cable to the conector, and a striped qwiic cable to the board headers sda and scl pins (d20, d21). No luck there. On the Mkr wifi 101 i use the striped qwiic cable to the headers sda, scl. This works ok and i can daisy chain multiple displays with qwiic cables.

7

Ah, I forgot the turbo had a qwiic connector.

I don’t have a turbo to try out but if I recall correctly you might need wire1 rather than wire to get spi running. Failing that, have a look at the sercom tutorial and see if you can create a spi bus on your chosen pair of pins.

https://learn.sparkfun.com/tutorials/ad … amd-boards

8

Wire1 seem not defined in the turbo… or i am missing something?

Thanks for the help by the way

9

There is indeed no wire1, it is Wire and it is using Sercom3. I have a Sparkfun Qwiic Micro, which also uses the SAMD21.

I have noticed with some testing in the past that if the device is using clock stretching the detection might fail with some processors. The detection is handled in the same way as the standard i2C scanner.

I don’t have this alphanumeric display but try the attached i2C scan. I added a line that helped in previous tests to enable detection. You can always give it a try.

i2cscan.zip (1.15 KB)

10

Thanks Paul, i tried but no luck… “No I2C devices found”. Then i tried this setup: Redboard turbo → qwiic cable to display → qwiic cable to a twist rotary : I2C device found at address 0x3F !

, it detecs the twist but not the display… so i suspect the display library…

11

very weird… the display library is not used when doing the I2Cscan. It is directly working with Wire and Wire is working else the twist rotary would not be detected.

Maybe try to change the Wire speed. default is 100K. See what happens with Wire.setClock(50000) after Wire.begin(). This will set for 50K.

Do you still have the pull-up resistors in place or removed ?

Any possibility to check the 3v3? It is used to with boost converter to create the 5V that is used for the chip?

12

i was busy and can not check, for the moment i switched to another Arduino board that gives me no problems. I tested whit pull ups and without, if i get some time i will check again the scanner with the clock speed reduced. thanks!