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SSD1306 FR Output

28 Sep 2018

While working on my version of a software library to control the SSD1306 OLED driver chip, I read about the FR output pin:

This pin outputs RAM write synchronization signal. Proper timing between MCU data writing and frame display timing can be achieved to prevent tearing effect.

This sounds perfect for my double buffering library. Unfortunately, the output pin is not connected to anything, even though there is an available connector on the ribbon cable, right next to it!

The datasheet for the SSD1306 shows the ribbon cable connections:

SSD1306 Ribbon Cable Connections

It’s possible to zoom right in, and see the problem, but first you need to figure out where the trace from the FR pin is. The pin definitions help:

SSD1306 FR Pin Definition

The FR is pin 51, and is located in-between the BS2 and CS# ribbon connections. I’ve coloured the FR pin dark blue in the following zoom in of the ribbon cable connections shown above.

SSD1306 Ribbon Cable Enlarged

Wouldn’t it have been nice if it was extended down to the ribbon cable connection labelled NC (for No Connection) that I coloured light blue?

After discovering this, I found out that the Arduboy uses the same OLED driver, and that their community has discussed the unavailable FR pin too: