Change GPIO AON clock speed

[jbzp00y]

Hello,

I saw this post to change the GPIO clock speed:

How to config GPIO clock freq?

We use 4 GPU GPIO to download the FPGA firmware on customer carried board. About the FPGA download , we use the same mode with a TX2 customer carried board. Download time:(the same Firmware file) 1） TX2 : about 120 seconds; 2） ORIN NX : about 370 seconds; How to reduce the download time on ORIN NX; Thanks

How to do the same thing for AON GPIO ? And what is the maximum speed I can reach ?

Thank you

[KevinFFF]

Hi jbzp00y,

Are you using the devkit or custom board for Orin NX?
What’s your Jetpack version in use?

Which GPIO would you like to control?

[jbzp00y]

Hi @KevinFFF

I use a custom board with Jetpack 5.1.1.

I want to control those gpios:

• JTAG_TMS: GPIO (Z.6)
• JTAG_TCK: GPIO (Z.7)
• JTAG_TDI: GPIO (CC.1)
• JTAG_TDO: GPIO (X.7)

I made a comparison with a Jetson Nano on a custom carrier board and result are very different.
The test is the toggle of a gpio with gpiod in a Linux driver.

Jetson Nano: 7.29MHz
Jetson Orin NX: 240kHz

If I increase axi_cbb I can reach 380kHz on Orin NX but it’s far away from Nano. Do you have some idea to increase this speed ?

[KevinFFF]

Jetson Nano and Orin Nano/NX are from different platform and also BSP release. The architecture and SW stack are so much different.

May I know what’s your use case for controlling GPIO with high speed?
Are you trying to transmitting some data through GPIO?

[jbzp00y]

Yes, I flash a FPGA with bit-banging

[KevinFFF]

@jbzp00y

If I increase axi_cbb I can reach 380kHz on Orin NX but it’s far away from Nano.

It seems 380kHz is the expected result for Orin NX.

Do you consider for other approach for your use case to update FPGA firmware? (like JTAG or serial communication?)

[jbzp00y]

I make JTAG with bit-banging. Is there any other way to perform this ?

[KevinFFF]

We would suggest using serial communication instead of bit-banging to transmit data if the current performance of bit-banging can’t meet your requirement.
and sorry that we don’t have FPGA to verify it on the devkit.

[jbzp00y]

It’s not possible to flash this FPGA with a serial communication.

So, it’s not possible to have the same performance on Orin NX that on Nano ?
There isn’t any hidden parameter ?

[KevinFFF]

It may mainly relate to the SW stack difference between R32 and R35.
GPIO is available to be controlled for both release w/o other parameter to constraint its performance.
If you have Xavier, you could also compare the performance between R32 and R35.