Hello again,
After several in-depth investigations, I am still facing an issue and a difficulty.
To be clear, I started from a clean installation of JetPack 6.2.1, and the only modification I made to the files is in tegra234-mb2-bct-misc-p3767-0000.dts:
cvb_eeprom_read_size = <0x0>;
I used the well-known command with p3509-a02-p3767-0000.conf:
sudo ./tools/kernel_flash/l4t_initrd_flash.sh --external-device nvme0n1p1 \
-c tools/kernel_flash/flash_l4t_external.xml \
-p "-c bootloader/generic/cfg/flash_t234_qspi.xml" \
--showlogs --network usb0 p3509-a02-p3767-0000 external
And the HDMI video output still does not work.
As for the difficulty, I cannot link the I2C index in the files with the Jetson pins.
I extracted from the TRM DP-10508-002:
- I2C instance I2C4 ⇒ Verilog ball names
DP_AUX_CH1
- I2C instance I2C6 ⇒ Verilog ball names
DP_AUX_CH0
- I2C instance I2C7 ⇒ Verilog ball names
DP_AUX_CH2
with
- block name i2c4 ⇒
0x03190000
- block name i2c6 ⇒
0x031b0000
- block name i2c7 ⇒
0x031c0000
But when I look at tegra234-p3768-0000+p3767-0001-nv.dts:
aliases {
i2c3 = "/bus@0/i2c@3190000";
i2c5 = "/bus@0/i2c@31b0000";
i2c6 = "/bus@0/i2c@31c0000";
};
__symbols__ {
dp_aux_ch1_i2c = "/bus@0/i2c@3190000";
dp_aux_ch0_i2c = "/bus@0/i2c@31b0000";
dp_aux_ch2_i2c = "/bus@0/i2c@31c0000";
}
Although the assignment of the I2C buses with the DP_AUX pins seems consistent, I still get different indices for I2C.
I managed to use the dcb_tool by rewriting the files:
./dcb_tool -r tegra234-dcb-p3767-0000-hdmi.dtsi
Output:
=== Reading DCB blob ===
########## Tegra DCB BLOB ###############
########### Display Devices #############
Display Devices::
Display Devices : [0]
Type : [TMDS]
CCB : [0]
Heads : 0:[Y] 1:[Y]
Sor : [0 ]
HDMI capable : [1]
Connector : [0]
Bus : [0]
############### CCB Entries ###############
CCB::
*CCB entries that have both I2C and AUX ports unused (value = 31) are not displayed
CCB Index : 0
I2C Port : [6]
AUX Port : [0]
########### Connector entries #############
Connectors::
Connector Index : 0x0
Type : [HDMI]
Hotplug : A:[Y]
I see that the I2C port used is 6.
- If I use the TRM index, this corresponds to pin
DP_AUX_CH0.
- If I use the DTS file index, this corresponds to pin
DP_AUX_CH2.
However, as far as I know, I am using pins 98 and 100 of the Jetson, which correspond to DP_AUX_CH1. And indeed, these are the pins used on the P3509 carrier board.
Could you explain how to map the TRM information to the physical Jetson pins? This applies both for I2C and for pin 96, which is used as HDMI hotplug.
Then, I realized that pins 98 and 100, which should function as the HDMI I2C bus, have an incorrect voltage.
On my custom carrier board, when these pins are left floating, I measure a voltage of 40 mV.
As the I2C master, shouldn’t the Jetson be driving these pins at 3.3 V?
It looks like these pins are always configured for DP. How can I check this?
Thank you in advance for your answers and for the time you are taking to look into my request.
