04-11-2018, 09:45 AM
Hello all,
I'm trying to connect an MCP23017 to the i2c bus on one of the Clusterboard's headers (J4) and I'm unable to see it from Linux using i2cdetect:
I had the same problem interfacing this same chip to a full-size A64 board and resolved it by adding some pull-up resistors to the i2c pins (connecting them to the 3.3v supply as suggested in this thread: https://forum.pine64.org/showthread.php?tid=2079&page=2). However the Clusterboard doesn't supply 3.3v at this header.
I'm not sure how best to proceed. Assuming the pull-ups are required on the Clusterboard as they are on the A64, do I need to provide a 3.3v supply (perhaps stepping the 5v supply down to 3.3v) or is there a better way to achieve the same thing?
It seems weird to me that the header would supply the i2c pins if they couldn't work without external regulation but then again I'm pretty new to working with i2c and maybe this is normal?
Any pointers are appreciated, thanks!
I'm trying to connect an MCP23017 to the i2c bus on one of the Clusterboard's headers (J4) and I'm unable to see it from Linux using i2cdetect:
Code:
jjg@pine64so:~$ sudo 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: -- -- -- -- -- -- -- --
jjg@pine64so:~$ sudo 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: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- -- I had the same problem interfacing this same chip to a full-size A64 board and resolved it by adding some pull-up resistors to the i2c pins (connecting them to the 3.3v supply as suggested in this thread: https://forum.pine64.org/showthread.php?tid=2079&page=2). However the Clusterboard doesn't supply 3.3v at this header.
I'm not sure how best to proceed. Assuming the pull-ups are required on the Clusterboard as they are on the A64, do I need to provide a 3.3v supply (perhaps stepping the 5v supply down to 3.3v) or is there a better way to achieve the same thing?
It seems weird to me that the header would supply the i2c pins if they couldn't work without external regulation but then again I'm pretty new to working with i2c and maybe this is normal?
Any pointers are appreciated, thanks!
