When uploading with the Arduino IDE, I get a lot of "(expected 4, got -5)" warnings and then "avrdude: verification error; content mismatch"
Can Gemma drive Neopixels (strips, squares, etc)? How many?
To use with neopixels:
- Connect the + power line of the strip to Vout on the Gemma, or to a separate 4-7VDC power source such as a 3 or 4 pack of AA batteries.
- Connect the - common ground to the battery pack (if being used) and also to the Gemma GND pin
- Connect the data in line to Gemma #1 - this will let you also see when data is being sent because the #1 red LED will flicker. You can use other pins but start with #1 since its easiest to debug and use
- Install the NeoPixel library as detailed in our Uber Guide, and change the PIN to 1 (its 6 by default)
- Upload and enjoy!
Can Gemma use the Flora Lux/Compass/Accelerometer/Color/GPS Sensors?
Can Gemma drive your Adafruit I2C LED Backpacks for 7-segment/matrix displays?
That tutorial also shows how to use the TinyM I2C driver, which works great on the ATtiny85, and adapt other existing libraries for the Gemma/Trinket
Can Gemma drive a Servo?
Gemma runs at 8MHz, but I really need it to run at 16 MHz, is this possible?
However, the AVR series is pretty forgiving for overclocking, so you may be able to run the 3V Gemma at 16 MHz. Note that this is still overclocking, your code may run flakey or not at all! Overclocking should not damage the AVR, but we still recommend sticking with 8 MHz only if you can get away with it!
To run at 16Mhz, use the Trinket 16Mhz board definition and modify your sketch as described here.