I2c problem on gl-ar750 (white)

Technical Support for Routers
1

I have been trying to get an I2C clock up and going on the gl-ar750 (the one in the white enclosure) using the i2c pins which are already populated on the device and they do not seem to work. I compiled a custom openwrt (from gl-inet github) and have the i2c-custom seems to be properly configured from what I can tell. However, whensing i2cdetect I do not see anything on the i2c bus. (i2cdetect -r -y 0)

I have a gl-ar750s (grey with external antenna) which I soldered a header on for the i2c and that works flawlessly, so I know the RTC I’m trying to use works.

I’m curious if anybody has gotten the i2c bus working on the gl-ar750 and if they have any suggestions.

2

Which two gpios do you use?

3

The header on the ar-750 is pre-populated and the pins were gpio-17 (sda) and gpio 16 (scl) according to the pre-configured module.

4

By comparing the schematic diagram of the two products, AR750 has 10K pull-up resistance on SDA, while AR750S does not
Do you also have pull-up resistors on your RTC?

5

I’m pretty sure the RTC modules already pull-up resistors on them, so that is a problem. However I have some other devices which don’t have resistors on them that also don’t work. Ultimately I’d like to figure this out, but I have a device with the ar750s which is working as expected, so I’m not quite as annoyed as I could be.