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bitbank2 / BitBang_I2C

A software I2C implementation to run on any GPIO pins on any system
GNU General Public License v3.0
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Raspberry Pi: how to initialize the lib for default hardware i2c-0/1 and how to specify OLED type and i2cAddr directly? #21

Closed dsyleixa closed 3 years ago

dsyleixa commented 3 years ago

hi, for the Raspberry Pi (OS Stretch): how to initialize the lib for default hardware i2c-0 and/or i2c-1 (pin numbers? which numbering (BCM, physical)? or how else?) how to specify an arbitrary OLED type (e.g. SSD1306) and how to specify i2cAddr directly (no autodetect, e.g. 0x3c)?

(AFAIK changing the system i2c clock speed is not possible)

bitbank2 commented 3 years ago

See the pigpio documentation for how pin numbers are mapped (that's what's used within BitBang_I2C on the RPI). The OLED type is specified with a constant defined in ss_oled.h The OLED address is auto-detected (see line 792 in ss_oled.c) The I2C clock speed of the RPI can be set to a max of 400K see here: https://www.raspberrypi-spy.co.uk/2018/02/change-raspberry-pi-i2c-bus-speed/

dsyleixa commented 3 years ago

ok, pin numbers then probably by BCM-numbering, so for i2c-1 probably SDA=2 , SCL=3 DEVICE_SSD1306 is the 1st one mentioned in the 2nd enum line, so perhaps = 1?

But I would like no i2c-auto-detect but explicitely set the i2cAddr explicitely : is that not possible?

bitbank2 commented 3 years ago

So set the address. If it's -1, then it auto-detects. The pin numbers are only needed if you want to bit-bang the I2C protocol. If you want to use the hardware I2C, then you don't need to provide pin numbers.

dsyleixa commented 3 years ago

sorry, I am quite a beginner, it's completely confusing me... how would the command line look like to initialize the lib for standard i2c-1 SSD1306 addr 0x3c

bitbank2 commented 3 years ago

Look at the examples in ss_oled. The code on the RPI will be basically identical.