Elton User Manual Rev 1.04
Page 58
17. ADDENDUM
The following section provides additional information and instructions relevant to the components specified
in the Main Sections of this document.
Programming NXP PTN3460 Chip
NOTE
: Conventionally, the PTN3460 chip is packaged pre-programmed by the integrated circuit
manufacturer. The following instructions have been provided as an additional resource.
The LVDS interface can be configured using multi-level configuration pins (CFG1, CFG2, CFG3, and CFG4)
or through the Register interface.
The register interface provides a greater level of flexibility in configuring parameters relevant to LVDS output
swing, spreading depth and more, than the multi-level configuration parameters available on pins.
The PTN3460 integrates a register interface that can be accessed by CPU/GPU or System Controller to
configure and customize settings. The registers can be read/written to, either via DP AUX or I2C-bus
interface. The register settings override the pin values.
All registers must be configured during power-on initialization after the HPDRX
pin pulse
is HIGH.
By default, the GPIOs for PTN3460 are in Power-Down mode and must be programmed to Power-Up by
invoking a script session using the following script.
home/nvidia/lvds-en.sh
Enter the following command lines in the terminal to run the script.
cd /home/nvidia
sudo ./lvds-en.sh
Using the
sysfs
interface, enter the following command lines:
#sudo su
#echo 490 > /sys/class/gpio/export
#echo out > /sys/class/gpio/gpio490/direction
#echo 1 > /sys/class/gpio/gpio490/value
The
/sys/class/gpio/export
string exports a GPIO pin based on the pin name/number entered in the
string and makes it visible in the sysfs file system.
The
/sys/class/gpio/gpio490/direction
string sets the GPIO direction to in/out. If it is an output
pin, the command sets the level to low or high.
The
/sys/class/gpio/gpio490/value
string sets the GPIO output value to 0/1 (low or high).
Using I2Ctools
The LVDS functionality is implemented through the eDP to PTN3460 LVDS bridge interconnectivity.
For the display screen to transmit LVDS signals, it must be capable of communicating with the video source.
EDID (Extended Display Identification Data) structures the data for the display using EDID communication
protocols.
The DP AUX interface on the PTN3460 transports i2c (Inter-Integrated Circuit}-over-AUX commands and
supports EDID-DDC communication with the LVDS panel. To support panels without EDID ROM, the
PTN3460 can emulate EDID ROM behavior.
The i2c address on the PTN3460 chip is 0x20 and resides on Bus 2.
