Nazar Gerasymchuk Posted January 28, 2019 Posted January 28, 2019 Armbianmonitor: http://ix.io/1zpY I have few of i2c devices that was successfully tested working with RPi Zero W (Tiny RTC, BME280), but no one is visible to NanoPi Neo Air board with Armbian. I can't get it to work on latest few versions of Armbian. As soon as I add i2c0 to overlays there appears two of i2c devices (both silent): $ ls -la /dev/i2c* crw-rw---- 1 root i2c 89, 0 Jan 28 14:58 /dev/i2c-0 crw-rw---- 1 root i2c 89, 1 Jan 28 14:58 /dev/i2c-1 I need to admit that scan itself took quite significant amount of time. $ sudo time 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: -- -- -- -- -- -- -- -- 0.00user 0.04system 3:59.62elapsed 0%CPU (0avgtext+0avgdata 1036maxresident)k 0inputs+0outputs (0major+64minor)pagefaults 0swaps Since it could be a problem with pull-up resistors, I've tried to add 4K7 resistors to SDA and to SCL lines, but situation remains the same. What am I doing wrong? What step is missed? Will appreciate any help. Thank you.
martinayotte Posted January 28, 2019 Posted January 28, 2019 51 minutes ago, Nazar Gerasymchuk said: could be a problem with pull-up resistors Yes, since there are no ones onboard ... 52 minutes ago, Nazar Gerasymchuk said: What am I doing wrong? Don't know ... Could be that you mistakenly crossed SDA and SCL ?
Nazar Gerasymchuk Posted January 28, 2019 Author Posted January 28, 2019 Thank you for quick response, @martinayotte > Could be that you mistakenly crossed SDA and SCL ? Checked and re-checked for a lots of times, tried different jumpers and different breadboards. Unfortunately I have no oscilloscope to check if i2c bus is working, but are there any ways to test the bus? E.g.: what does it means if i2cdetect scan takes so much time? Could it signalize something?
martinayotte Posted January 28, 2019 Posted January 28, 2019 8 minutes ago, Nazar Gerasymchuk said: what does it means if i2cdetect scan takes so much time? "i2cdetect -y 0" should be almost instantenous, left than half second for the whole 127 addresses ! If it takes about 1 seconds per address, this means you pullups are defective, or they are placed on the wrong pins.
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