HOW TO USE TX1 UART3

Hi all :

We tried to use uart3 to communicate with peripherals design part,I know /dev/ttyTHS2 is maped uart1,but /dev/ttyTHS1 and /dev/ttyTHS3 without effect.How can we use UART3 ?

Thank you!

Hi dittoxjj,

If you are asking about UART3 pins of the module, it doesn’t really have any signal output. Please refer to “UART” section of http://developer.nvidia.com/embedded/dlc/jetson-tx1-oem-product-design-guide

thanks for your help!
uart3 use for WiFi/Bt is means I can not use uart3 as uart function?

Do I have to change the hardware ?

WiFi/BT connection is inside the module and UART3 pads of the module have no real hardware pin out from tegra. So you cannot use UART3 of the module.

There are 5 UARTs routed out on JTX1 board to board connector.

UART0(TX1_UART1) is for debug use which routed to J10 Debug connector and J21 Expansion Header, There is a UART MUX auto switcher(When the 60-pin debug connector J10 is being used UART is routed to the 60-pin debug connector J10, When the 60-pin debug connector J10 is NOT being used UART is routed to the 40pin stake pin header J21).
UART1(TX1_UART3) is routed to J17 with 1v8 to 3v3 level shift.
UART2(TX1_UART2) is routed to J18 M.2 Key E slot.
UART3(TX1_UART4) have a NO STUFF 0ohm resistor connect to J21(UART1_HDR_3V3). TX1_UART4 is also have NOT STUFF 0ohm resistor on JTX1 CVM board which default is routed to WIFI/BT chip. This UART can’t be used at all.
UART4(SNN_J1_RSVD), this is not connected signal on JTX1 CVM.

You could use the UART1(TX1_UART3) on J17 of P2597 carrier board for general use.

Thanks very much!