greiman / SSD1306Ascii

Text only Arduino Library for SSD1306 OLED displays

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Atmega328PB SSD1306AsciiAvrI2c issues

ZL1CVD opened this issue · comments

FYI - some end user feedback for you.

I have had huge stability problems when using SSD1306AsciiAvrI2c.h

Display starts then randomly everything locks up. Tried a wide range of speeds using oled.setI2cClock which did prove some speeds withing a range worked better than others.

Changed code to use Wire SSD1306AsciiWire.h and all issues resolved EXCEPT now have low memory. But it does work.

Wire has lots of timeouts and resets so it tends not to hang with marginal devices. There are two places in AvrI2c that could hang and I plan to add a timeout and reset to these. Unfortunately I don't have a marginal device to verify the fix.

I suspect most most devices hang on an I2C stop so a reset probably would cause limited glitches since it may occur after all data is sent to the device.

I am currently using AvrI2c in a minimal size RTC library so maybe I will find a marginal RTC chip.

I replace AvrI2c.h with one that has time-outs and some other mods. It shouldn't hang in a loop waiting for an I2C command to complete.

If there are glitches in the display we can pursue these. Debug prints can be enabled in AvrI2c.h at about line 78.

I did some experiments an found a hang was possible if the I2C bus didn't have pull-ups.

Thank you. Stability issue resolved. I have not managed to lock up even once.
Now compiled code is bigger than Arduino IVR even with LTO enabled. This no longer such an issue for me as I reduced serial TX/RX buffer size to accommodate arduino wire code.