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I am trying to read bme280 & tsl2561 on Pi Zero. I have connected bme280 to Pi Zero on Pin 3-I2C.1 SDA & Pin 5-I2C.1 SCL and was able to read the data over i2c following these instruction. Then connected tsl2561 to Pin 27-I2C.0 SDA & Pin 28-I2C.0 SCL.

When I list I2C connected devices with ls /dev/*i2c* it shows me just /dev/i2c-1. Why I am seeing just one device ?

Output of i2cdetect -y 1 was

0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- 76 --

when I tried i2cdetect -y 0 got

Error: Could not open file `/dev/i2c-0' or `/dev/i2c/0': No such file or directory

Also tried to run TSL2561.py but got following error

$ python TSL2561.py
Traceback (most recent call last):
  File "TSL2561.py", line 16, in <module>
    bus.write_byte_data(0x39, 0x00 | 0x80, 0x03)
IOError: [Errno 121] Remote I/O error

Are Physical pin 27 & 28 are Pin 27-I2C.0 SDA & Pin 28-I2C.0 SCL respectively on Pi Zero W ? If yes what I need to do to activate them to read tsl2561 through them ?

Kernel Version : Linux pod01 4.14.79+ #1159 Sun Nov 4 17:28:08 GMT 2018 armv6l GNU/Linux

1

I²C.0 is reserved for system use.

It is only on the header for use by HATs.

  • How can I user other GPIO for I2C, since I2C.1 already consumed ? – roy Jan 18 at 3:25
  • 1
    @roy you can connect many I²C devices to the interface, provided they have unique addresses. – Milliways Jan 18 at 3:27

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