i2cdetect shows every possible address

Question

I was trying to turn on I2C following this tutorial http://www.raspberrypi-spy.co.uk/2014/11/enabling-the-i2c-interface-on-the-raspberry-pi/

But I have problem which I cannot solve. The command i2cdetect -y 1 returns

     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          03 04 05 06 07 08 09 0a 0b 0c 0d 0e 0f
10: 10 11 12 13 14 15 16 17 18 19 1a UU 1c 1d 1e 1f
20: 20 21 22 23 24 25 26 27 28 29 2a 2b 2c 2d 2e 2f
30: 30 31 32 33 34 35 36 37 38 39 3a 3b 3c 3d 3e 3f
40: 40 41 42 43 44 45 46 47 48 49 4a 4b 4c 4d 4e 4f
50: 50 51 52 53 54 55 56 57 58 59 5a 5b 5c 5d 5e 5f
60: 60 61 62 63 64 65 66 67 68 69 6a 6b 6c 6d 6e 6f
70: 70 71 72 73 74 75 76 77

I don't know why it shows all addresses and how can I fix this. I didn't connect anything to my Raspberry Pi. I've just put SD card and installed default OS using NOOBS. But when problem appeared I connected my RTC DS1307 but it didn't affect on i2cdetect output.

score 18 · Accepted Answer · answered Jun 20 '15 at 21:22

Generally this happens because something is pulling SDA (pin 3) low.

The i2cdetect program checks for the existence of a device by sending its address then letting SDA float high. If the device exists it should pull SDA low to signal its presence.

Check your wiring to make sure SDA hasn't been inadvertently connected to ground.

score 2 · Answer 2 · answered Aug 17 '19 at 18:53

2

In my case it was because broken i2c device was connected (I accidentally reverse connected it to voltage/ground before)

Try using another i2c device

answered Aug 17 '19 at 18:53

Karol Zlot

123
3

score 2 · Answer 3 · answered Sep 24 '20 at 15:01

2

I fixed this with a restart. I'm not sure what was wrong but I suspect it had something to do with me using the SDA pin for a button before I tried setting up the i2c module. I'm adding this just in case someone else has made a similar mistake.

answered Sep 24 '20 at 15:01

Cosmicfool

21
1

score 2 · Answer 4 · answered Feb 04 '22 at 16:28

2

I saw this happen when I was using the wrong AC adapter; switching to an 'official' AC adapter cleared up the problem for me.

answered Feb 04 '22 at 16:28

cloudxix

121
2

score 1 · Answer 5 · answered Sep 08 '18 at 17:43

1

Fixed my PI zero... Near SDA (pin 3) and the SD card slot there are two resistors, touched the connections with a soldering iron and it works now.

answered Sep 08 '18 at 17:43

Peter

11
1

i2cdetect shows every possible address

5 Answers5