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SSD1305 on SPI breaks under v2.x lib
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SSD1305 on SPI breaks under v2.x lib

by Nicodema on Thu Oct 08, 2020 3:11 pm

I've got a SSD1305 based 128x32 OLED display set up to work off SPI, that works just fine on either Trinket M0 or MKRZERO board, under the v1.x of the Adafruit SSD1305 library. Trouble there is the horizontal flip/4 pixel offset problem, so I thought try the v2.1 fix.

With the switch over to using the Adafruit_GrayOLED in the GFX library, the SPI stops working entirely. I have a Saleae logic analyzer hooked up to the SPI lines and I get full data in 1.0.3, but nothing at all in 2.1.1

I've tried both Hardware SPI and software, same deal.

This goes for either board, Trinket M0 or MKRZERO. I haven't tried any old AVR based Arduinos, since the SSD1305 is 3.3v max and what I have is all 5v, Micro, Nano , Mega2560 etc.

I'm using GFX lib 1.10.1 , but I believe only the v2.x of the SSD1305 library uses the GrayOLED code in it rather than local SPI handling in the 1305 lib.

Am I the only one getting this bizarre behaviour? Am I missing something simple?

Nicodema
 
Posts: 8
Joined: Tue Dec 18, 2018 8:46 pm

Re: SSD1305 on SPI breaks under v2.x lib

by Nicodema on Fri Oct 09, 2020 4:43 am

Breakthrough!
I tried again this morning, with the latest libs (SSD1305 2.1.1 & GFX 1.10.1)
The demo sketch, ssd1305test, still came up blank...
...until I opened the serial monitor window. At that point it sprang into life!
So I commented out the "while (! Serial) delay(100);"
Now it works fine.
When I looked back at the 1.0.3 sdd1305test code, it doesn't wait for the Serial at all. It seems an odd runtime dependancy to add to the demo sketch. I can't be the only one to fall for this gotcha. Can I?

Nicodema
 
Posts: 8
Joined: Tue Dec 18, 2018 8:46 pm

Please be positive and constructive with your questions and comments.