Using JetPack 3.3 on a J90 firmware version 1.6 patched to get USB3 working, I’m having trouble getting the UART2 port working. I tried both connecting TX and RX together as well as a USB cable to a PC. Currently /dev/THS1-3 are showing up as devices, however, these aren’t showing any output on /dev/THS1-3 or /dev/S0-3 using minicom.
UART0 works on /dev/ttyS0 on the J90, but we can’t use that as it is console and not DMA.
I also tried it on the dev board J17 and I’m not getting anything there either. If I flash with the device tree of the J90 does this break the dev board’s interface?
From much reading on the forums, there are patches to get the UART working, but I think most of them don’t apply to the versions I’m using, is this correct, or do I need to patch something to get this working? I’m not entirely sure where in the device tree to look to make sure it is enabled/mapped properly, could I get some pointers?
Edit: Dev board J17 UART1 does work with both the jetpack 3.3 default flash and the J90 firmware changes. Still can’t get J90 uart to work with their firmware or a built one from their sources.
From the J90 spec:
“UART2_TXD / SWCLKB16UART 0 console port (3.3V TTL level): transmit data output (RN24 must be installed) J90 with MCU: SWCLK”
What is RN24? Also, it is labeling uart2 port as uart0 console… Is that a typo? (Both UART0 and UART2 ports in the description say UART0 console…