Release v1.0

Description

The aim is to use an i2c bus of a raspberrypi like small computer to drive a led.

This first release is just to discover basic things : plug the hardware and play with it.

In this release i just want to blink one red led.

See v1.0 branch for code.

Pictures : Release v1.0

find pcf 8575 address

root@OrangePiH6:~# i2cdetect -y 0
Error: Could not open file `/dev/i2c-0' or `/dev/i2c/0': No such file or directory

It means there's no i2c bus at number 0, try again :

root@OrangePiH6:~# i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: 20 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

Fine, pcf8575 address is 0x20 and i2c bus as number 1

set pcf8575 ports

i2cset -y 1 0x20 0x01 0x00

• 1 = i2cbus (same as i2cdetect parameter, on pin 3 and 5)
• 0x20 = pcf i2c address (i2cdetect)
• 0x01 = p0 to p7
• 0x00 = p10 to p17

       p7  p6  p5  p4  p3  p2  p1  p0
0x01 =  0   0   0   0   0   0   0   1
       p17 p16 p15 p14 p13 p12 p11 p10

Don't forget : as in pcf8575 datasheet, leds are ON with a zero level... meaning that a value of 0x01 switch off led plugged on p0