i2c scan error

[mobi]

Hello,

I connected a sub-20 board to a Maxim MAX9526 Eva kit which has 3 i2c slave devices. However, I can only scan 1 of the devices. When using another USB-I2C board, I can successfully scan all 3 devices.

Is there a limitation on the number of devices supported for I2C mode?

By the way, I tried doing the scan using my linux workstation and my windows laptop and obtained the same result. It always return 1 device address.

Thanks.

[serg]

Hi,

Let me try to reproduce your issue. I will let you know my results ASAP

[serg]

Hi mobi,

I was not able to reproduce the issue reported in your post. I have used a setup of 3 sub-20 boards, where device
with s/n 0x0000 acted as an i2c master and devs 0x0068 & 0x0866 were configured as i2c slaves with i2c bus addresses 0x20 and 0x60 correspondingly.

i2c scan setup

i2c_scan.JPG (91.83 KiB) Viewed 8340 times

Therefore, most likely there is no problem of the sub-20 hardware/software with regard to the i2c scan functionality. Could you please try to send/receive 1 byte to both of your devices. Does it work? If no could you capture and send us oscilloscope images? If you say that another i2c master can detect both of the devices I would check electrical connections/ voltage levels /noice etc. Try to reduce the speed down to 100kHz. Anyway, in this particular case I think an oscilloscope would greatly help.