Hi,
I want use i2c-3. I read that DP_AUX_P and DP_AUX_N pins should be used as SDA and SCL for i2c-3. However in the schematics, they are shown as pulled down to ground. I checked in voltage in these pins and its indeed grounded. How can I use these pins for i2c? Do I need to change pin functions? Or add external pullup resistor?
Thanks
I pulled up DP_AUX_P and DP_AUX_N to 3.3V. Still slave is not being detected. Are there some software changes to be done to use i2c-3?
I assume you are talking about Jetson TK1.
Those pins are marked for LVDS/DP. Why do you want to use them for I2C? From where did you read the you should use those pins for I2C-3?
The associated voltage rail for those pins is marked as 1.05V in the dev kit specification. Pulling them to 3.3V might do all kinds of damage.
There are a generic I2C pins both for 1.8V and 3.3V in the expansion header, pull-ups included. Could you use those?
Hi goutamgmb
DP_AUX is mapped to I2C6 on Jetson according to both
https://developer.nvidia.com/rdp/assets/jetson-tk1-development-platform-pin-mux
http://developer.download.nvidia.com/embedded/jetson/TK1/docs/3_HWDesignDev/TegraK1_Embedded_DG_v03.pdf
You can’t choose I2C3 for DP_AUX pins on pinmux either.
GEN1_I2C I2C1
GEN2_I2C I2C2
CAM_I2C I2C3
DDC_I2C I2C4
PWR_I2C I2C5 or also called I2CPMU
DP_AUX I2C6
According to eDP spec, there should be no 100KΩ pull-down resistor on AUX CH_P.
however we could bring up eDP panels on Jetson w/o removing 100KΩ pull-down on DP_AUX_P.
so I don’t think removing 100 KΩ pull-down rework is required on Jetson’s DP_AUX_P.
DP_AUX pull up & VDDIO_HV for DP_AUX port are already powered by 3.3V rail by default on Jetson.