[SOLVED] i2cdetect doesn't detect anything

[dave-at-axon]

Ok, I was just wondering why these addresses were showing some times and some times not.

The pullups??

Remove them and see if this cures the issues.

[dave-at-axon]

On which bus did you connect your i2c devices ?
because the i2c-1 bus is the one where the AXP chip is connect.
With my A20 board, I've some i2c devices on UEXT1 and they are seen on i2c-2.

Mmmmm.

On the schematic the AXP209 is on TWI-0. I can confirm this as I have my LCD touch on this and on my original dev board, I got errors on TWI-0 from the AXP209 code when I powered down the touch driver.

My RTC is on TWI-1 and my analog inputs are on TWI-2 and both come from the UEXT connections.

Which OS are you using? The above is based on Android. This is the entry from the FEX file and these ports match with the schematic.

Code Select Expand


[twi0_para]
twi0_used = 1
twi0_scl = port:PB00<2><default><default><default>
twi0_sda = port:PB01<2><default><default><default>

[twi1_para]
twi1_used = 1
twi1_scl = port:PB18<2><default><default><default>
twi1_sda = port:PB19<2><default><default><default>

[twi2_para]
twi2_used = 1
twi2_scl = port:PB20<2><default><default><default>
twi2_sda = port:PB21<2><default><default><default>


[martinayotte]

Hi Dave,

You're right, I've confused myself between AXP and the EEPROM.
what I have is the following, but my own temp sensor (4B) attached on UEXT1 is still on bus #2 :

root@A20:~/LDC-indoorcom# i2cdetect -y 0
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- UU -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --                         
root@A20:~/LDC-indoorcom# 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: 50 51 52 53 54 55 56 57 -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --                         
root@A20:~/LDC-indoorcom# i2cdetect -y 2
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- 4b -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --                         

[Shakipu]

I removed the pullups of the TSL2561 at works today but when I came back home to try it, it seems that all of my sensors were broken... I tried them with an Arduino but there is definitely a problem : the TSL2561 return me an overload error and nothing happens for the BMP180. I haven't made any changes on my wiring... God thanks, my GPS and OlinuXino still works... I will try to find out what happened but I don't have all my tools where I am (I am temporarily out of my real home for work).

I think that sleeping with the window open and the components next to the window isn't a good thing. Especially when it's raining outside and there is thunderstorms...

[Shakipu]

Hi everyone,

time has passed since my last try with i2c but today it is a success. I got the TSL2561 communicate with my A20 and I can now go on further developments. The BMP180 looks definitely broken so I may buy one that is better or find what is broken on my BMP180 and try to repair it.

I think that the fix for my i2c problem was to remove the pullups resistors. Thank you everyone !