Bill Greiman

I decided to make a change so PrintFile builds correctly. I added an exception for SAM_DUE. The board package for Due clearly has a bug with flush() being in Stream...

I have no idea how to use SPI3 on a ESP32 S3 and don't have one so I can't experiment. I suggest you try this simple program to see if...

@mjs513 I am not sure what the fix is. 5V devices run at slightly over 400kHz, 3.3V have some rate less than 400kHz. It appears to vary a lot depending...

@mjs513 Thanks for your post. I decided to play with pullup resistor size and pullup voltage. Case with bigger resistor. Rate goes from above 325 kHz to 285 kHz. ...

Adding a 5V device makes the 3.3V device go faster. The 5V pullup causes the clock to have higher peak voltage. 

@paulvha > Just out of interest.. did you connect to the Qwiic connector I did not use Wire1 on the Qwiic connector. I think there is a good chance a...

> Just out of interest.. did you connect to the Qwiic connector I did. Works like a charm with a SDD1306 display on Wire1.  I looked at many captures...

@paulvha I agree. Too bad the R4 Minima has only the 5V Wire. The Uno R3 works well with 3V3 I2c since at the time the AVR I2C controller was...

I checked the RA4M1 datasheet for I2C Vih and it is the the standard value:  Then I realized I didn't know what Vcc is in my tests using USB....

Doesn't matter, too many problems for me to use R4.