Teensy 2.0 & SSD1306 OLED display test
This is my little program to drive an SSD1306-based 128x32 OLED display from a Teensy 2.0 (atmega32u4-based board) using I2C.
Hardware
The hardware is very simple - a Geekcreit 0.91 Inch 128x32 I2C blue
OLED
display),
driven by a Teensy 2.0. The hardware side is extremely simple - drop
them both in a breadboard, wire up power and ground, connect SCL to
D0 and SDA to D1.
Software tooling
As I'm developing on a Mac, I installed Crosspack
AVR. I'm using
teensy_loader_cli
to program the Teensy, and
hid_listen from
pjrc.com to supply debug output. The utilities source and Makefile
come from pjrc's "blinky"
example.
The code
- This is my first AVR coding project, so I've made plenty of use of the ATmega32U4 datasheet.
- The Geekcreit module has no data sheet, so I've relied on the SSD1306 datasheet, which I've included in the repo, since it's handy and not quite as common as the AVR.
- This is my first attempt at bit-banging IIC (my previous Z80-based computer talked to its SD card using bit-banged SPI, though!). I found https://learn.sparkfun.com/tutorials/i2c/all to be a very helpful tutorial.
- While I'm writing the interface code from scratch (where's the sense of achievement, otherwise? ;), it's useful to refer to others' work, making sure you're not on the completely wrong track. https://github.com/olikraus/u8glib/blob/master/csrc/u8g_dev_ssd1306_128x32.c was helpful while attempting to get the first bring-up working.