The Nibble uses the ST7735 green tab 128x128 display. The firmware uses the Display library in our custom-made CircuitOS framework, which relies on the TFT_eSPI library. When you first start CircuitBlocks, it will automatically download our Nibble esp8266 core (based on the regular esp8266 Arduino core), along with CircuitOS and the TFT_eSPI library, among other libraries that are required to compile programs for the Nibble. You can then program any program for the Nibble using CircuitBlocks, or just opening up a new Arduino IDE sketch for the CM Nibble device.
Of course, you can also program the Nibble and it’s display completely without relying on CircutOS. Just select the CM Nibble device in Arduino IDE, or open a Nibble code project in CircuitBlocks, and use the TFT_eSPI library which is already provided by programming a sketch for the Nibble.
A problem might occur if you also have the TFT_eSPI library in your Arduino libraries folder. Arduino IDE and CB will then prefer to use that library instead of the one provided with the Nibble core, which might not have the same display pin configurations for the display in the library User_Setup.h configuration file.
To make sure you are using the right display library, please temporarily remove the TFT_eSPI lib in your Arduino libraries directory. Unfortunately, due to the nature of how Arduino selects libraries used when compiling, and the library itself, it is currently not possible to handle this in any other way.
It is currently planned to write up a full documentation on the Nibble firmware, and the CircuitOS framework which we base all our device’s firmware on, so we should publish that some time between our STEM Box fulfilments.
Hope this helps,