Which Commands do I have to use SSD1306 over I²C? - c

Question

I want to create a simple linux driver for the SSD1306 that I have connected to my Raspberry Pi over I²C.
Before I start coding, I want to get to know the device and which commands I have to send. I use the i2c-tools for linux to test my commands. I studied some Arduino projects and the datasheet of the SSD1306, but I could only recreate a few commands on the commandline:
Initializing the device: i2cset -y 1 0x3c 0xAE 0x20 0x10 0xb0 0xc8 0x00 0x10 0x40 0x81 0x7f 0xa1 0xa6 0xa8 0x3f 0xa4 0xd3 0x00 0xd5 0xf0 0xd9 0x22 0xda 0x12 0xdb 0x20 0x8d 0x14 0xaf i
Send data to the device's memory: i2cset -y 1 0x3c 0x40 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF 0xFF i
This fills some Pixels from the current position to the right.
Jumping to the upper left pixels: i2cset -y 1 0x3c 0xb0 0x00 0x10 i
This didn't always work :(
0x3c is the address of my SSD1306 device
I would be glad if someone could tell me some more commands or knows where I can find a good example or tutorial with comments.
Thanks,
p0kR

Answer 1

here's an extended example inspired by https://www.mikrocontroller.net/topic/390980:
function display_off() {
i2cset -y 0 0x3c 0x00 0xAE # Display OFF (sleep mode)
sleep 0.1
}
function init_display() {
i2cset -y 0 0x3c 0x00 0xA8 # Set Multiplex Ratio
i2cset -y 0 0x3c 0x00 0x3F # value
i2cset -y 0 0x3c 0x00 0xD3 # Set Display Offset
i2cset -y 0 0x3c 0x00 0x00 # no vertical shift
i2cset -y 0 0x3c 0x00 0x40 # Set Display Start Line to 000000b
i2cset -y 0 0x3c 0x00 0xA1 # Set Segment Re-map, column address 127 ismapped to SEG0
i2cset -y 0 0x3c 0x00 0xC8 # Set COM Output Scan Direction, remapped mode. Scan from COM7 to COM0
#i2cset -y 0 0x3c 0x00 0xC0 # Set COM Output Scan Direction, remapped mode. Scan from COM7 to COM0
i2cset -y 0 0x3c 0x00 0xDA # Set COM Pins Hardware Configuration
#i2cset -y 0 0x3c 0x00 0x12 # Alternative COM pin configuration, Disable COM Left/Right remap
#i2cset -y 0 0x3c 0x00 0x2 # Sequential COM pin configuration, Disable COM Left/Right remap
#i2cset -y 0 0x3c 0x00 0x22 # Sequential COM pin configuration, Enable Left/Right remap (8pixels height)
i2cset -y 0 0x3c 0x00 0x32 # Alternative COM pin configuration, Enable Left/Right remap (4pixels height)
#i2cset -y 0 0x3c 0x00 0x81 # Set Contrast Control
#i2cset -y 0 0x3c 0x00 0xCF # value, 0x7F max.
i2cset -y 0 0x3c 0x00 0xA4 # display RAM content
i2cset -y 0 0x3c 0x00 0xA6 # non-inverting display mode - black dots on white background
i2cset -y 0 0x3c 0x00 0xD5 # Set Display Clock (Divide Ratio/Oscillator Frequency)
i2cset -y 0 0x3c 0x00 0x80 # max fequency, no divide ratio
i2cset -y 0 0x3c 0x00 0x8D # Charge Pump Setting
i2cset -y 0 0x3c 0x00 0x14 # enable charge pump
i2cset -y 0 0x3c 0x00 0x20 # page addressing mode
i2cset -y 0 0x3c 0x00 0x20 # horizontal addressing mode
#i2cset -y 0 0x3c 0x00 0x21 # vertical addressing mode
#i2cset -y 0 0x3c 0x00 0x22 # page addressing mode
}
function display_on() {
i2cset -y 0 0x3c 0x00 0xAF # Display ON (normal mode)
sleep 0.001
}
function reset_cursor() {
i2cset -y 0 0x3c 0x00 0x21 # set column address
i2cset -y 0 0x3c 0x00 0x00 # set start address
i2cset -y 0 0x3c 0x00 0x7F # set end address (127 max)
i2cset -y 0 0x3c 0x00 0x22 # set page address
i2cset -y 0 0x3c 0x00 0x00 # set start address
i2cset -y 0 0x3c 0x00 0x07 # set end address (7 max)
}
display_off
init_display
display_on
reset_cursor
# fill screen
for i in $(seq 1024)
do
i2cset -y 0 0x3c 0x40 0xff
done
reset_cursor
# clear screen
for i in $(seq 1024)
do
i2cset -y 0 0x3c 0x40 0x0
done
reset_cursor
# draw a pattern
for i in $(seq 146)
do
for i in 1 4 16 64 16 4 1
do
i2cset -y 0 0x3c 0x40 $i
done
done
it is quite slow but works. tested with 128x32 oled display + raspberry pi 1.