Microdotphat on archlinux


#1

Microdot is not being detected via i2cdetect on a piZero W

ls -l /dev/i2c*

crw------- 1 root root 89, 0 Apr 6 11:48 /dev/i2c-0

i2cdetect -y 0

 0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f

00: – -- – -- – -- – -- – -- – -- –
10: – -- – -- – -- – -- – -- – -- – -- – --
20: – -- – -- – -- – -- – -- – -- – -- – --
30: – -- – -- – -- – -- – -- – -- – -- – --
40: – -- – -- – -- – -- – -- – -- – -- – --
50: – -- – -- – -- – -- – -- – -- – -- – --
60: – -- – -- – -- – -- – -- – -- – -- – --
70: – -- – -- – -- – --

works on raspbian as i2c-1

Thanks for any help
Fred


#2

Can you please post a photo of your soldering.


#3

Please note that same device (microdot and piZero W) under raspbian works as expected

ls -l /dev/i2c*

	crw-rw---- 1 root i2c 89, 1 Apr  5 16:16 /dev/i2c-1

# i2cdetect -y 1
 		0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
   10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
   20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
   30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
   40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
   50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
   60: -- 61 62 63 -- -- -- -- -- -- -- -- -- -- -- --
   70: -- -- -- -- -- -- -- --

It can’t be a soldering problem.

Fred


#4

I’m pretty sure it should work in Arch, although we don’t do any testing or official support of anything but Raspbian (there aren’t enough hours in the day or people on my team… yet). Have you tried Googling for Arch Linux Raspberry Pi i2c problems/solutions?

A quick Google suggests you should try updating via pacman -Syu


#5

Solved!
not sure why on raspbian buss 1 is activated with dtparam=i2c_vc=on and on arch it is buss 0.
Device overlays or i2c-bcm2708 driver, will require more research.

Adding dtoverlay=i2c1-bcm2708 to config.txt activated buss 1 under arch.

ls -l /dev/i2c-1
crw------- 1 root root 89, 1 Apr 8 15:00 /dev/i2c-1

# i2cdetect -y 1
 		0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
 00:          -- -- -- -- -- -- -- -- -- -- -- -- --
 10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
   20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
   30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
   40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
   50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
   60: -- 61 62 63 -- -- -- -- -- -- -- -- -- -- -- --
   70: -- -- -- -- -- -- -- --

All is good now.

Fred


#6

Thanks for posting your solution, I’ll have to remember this if it ever crops up again.