Reading UART serial data from M.2 connector using the Intel 8265 wifi/bluetooth module

Hi!

I have the Intel 8265 wifi/bluetooth module and I’m trying to read serial data on the M.2 connector’s UART from a bluetooth device that I’ve paired it with. I’m using an nRF51822 configured as a peripheral to send data to it and I’m trying to figure out how to receive the data with the Intel 8265 module.

I’ve been using the minicom to try to connect to the port and read data from it. I’ve found references online saying that it may be labeled as ttyS0. Is this correct?

Here’s a list of the tty devices available on my Jetson Nano B01 version:

crw-rw-rw-   1 root tty       5,   0 Apr 24 13:38 tty
crw--w----   1 root tty       4,   0 Apr 24 13:23 tty0
crw--w----   1 gdm  tty       4,   1 Apr 24 13:23 tty1
crw--w----   1 root tty       4,  10 Apr 24 13:23 tty10
crw--w----   1 root tty       4,  11 Apr 24 13:23 tty11
crw--w----   1 root tty       4,  12 Apr 24 13:23 tty12
crw--w----   1 root tty       4,  13 Apr 24 13:23 tty13
crw--w----   1 root tty       4,  14 Apr 24 13:23 tty14
crw--w----   1 root tty       4,  15 Apr 24 13:23 tty15
crw--w----   1 root tty       4,  16 Apr 24 13:23 tty16
crw--w----   1 root tty       4,  17 Apr 24 13:23 tty17
crw--w----   1 root tty       4,  18 Apr 24 13:23 tty18
crw--w----   1 root tty       4,  19 Apr 24 13:23 tty19
crw--w----   1 bsg  tty       4,   2 Apr 24 13:23 tty2
crw--w----   1 root tty       4,  20 Apr 24 13:23 tty20
crw--w----   1 root tty       4,  21 Apr 24 13:23 tty21
crw--w----   1 root tty       4,  22 Apr 24 13:23 tty22
crw--w----   1 root tty       4,  23 Apr 24 13:23 tty23
crw--w----   1 root tty       4,  24 Apr 24 13:23 tty24
crw--w----   1 root tty       4,  25 Apr 24 13:23 tty25
crw--w----   1 root tty       4,  26 Apr 24 13:23 tty26
crw--w----   1 root tty       4,  27 Apr 24 13:23 tty27
crw--w----   1 root tty       4,  28 Apr 24 13:23 tty28
crw--w----   1 root tty       4,  29 Apr 24 13:23 tty29
crw--w----   1 root tty       4,   3 Apr 24 13:23 tty3
crw--w----   1 root tty       4,  30 Apr 24 13:23 tty30
crw--w----   1 root tty       4,  31 Apr 24 13:23 tty31
crw--w----   1 root tty       4,  32 Apr 24 13:23 tty32
crw--w----   1 root tty       4,  33 Apr 24 13:23 tty33
crw--w----   1 root tty       4,  34 Apr 24 13:23 tty34
crw--w----   1 root tty       4,  35 Apr 24 13:23 tty35
crw--w----   1 root tty       4,  36 Apr 24 13:23 tty36
crw--w----   1 root tty       4,  37 Apr 24 13:23 tty37
crw--w----   1 root tty       4,  38 Apr 24 13:23 tty38
crw--w----   1 root tty       4,  39 Apr 24 13:23 tty39
crw--w----   1 root tty       4,   4 Apr 24 13:23 tty4
crw--w----   1 root tty       4,  40 Apr 24 13:23 tty40
crw--w----   1 root tty       4,  41 Apr 24 13:23 tty41
crw--w----   1 root tty       4,  42 Apr 24 13:23 tty42
crw--w----   1 root tty       4,  43 Apr 24 13:23 tty43
crw--w----   1 root tty       4,  44 Apr 24 13:23 tty44
crw--w----   1 root tty       4,  45 Apr 24 13:23 tty45
crw--w----   1 root tty       4,  46 Apr 24 13:23 tty46
crw--w----   1 root tty       4,  47 Apr 24 13:23 tty47
crw--w----   1 root tty       4,  48 Apr 24 13:23 tty48
crw--w----   1 root tty       4,  49 Apr 24 13:23 tty49
crw--w----   1 root tty       4,   5 Apr 24 13:23 tty5
crw--w----   1 root tty       4,  50 Apr 24 13:23 tty50
crw--w----   1 root tty       4,  51 Apr 24 13:23 tty51
crw--w----   1 root tty       4,  52 Apr 24 13:23 tty52
crw--w----   1 root tty       4,  53 Apr 24 13:23 tty53
crw--w----   1 root tty       4,  54 Apr 24 13:23 tty54
crw--w----   1 root tty       4,  55 Apr 24 13:23 tty55
crw--w----   1 root tty       4,  56 Apr 24 13:23 tty56
crw--w----   1 root tty       4,  57 Apr 24 13:23 tty57
crw--w----   1 root tty       4,  58 Apr 24 13:23 tty58
crw--w----   1 root tty       4,  59 Apr 24 13:23 tty59
crw--w----   1 root tty       4,   6 Apr 24 13:23 tty6
crw--w----   1 root tty       4,  60 Apr 24 13:23 tty60
crw--w----   1 root tty       4,  61 Apr 24 13:23 tty61
crw--w----   1 root tty       4,  62 Apr 24 13:23 tty62
crw--w----   1 root tty       4,  63 Apr 24 13:23 tty63
crw--w----   1 root tty       4,   7 Apr 24 13:23 tty7
crw--w----   1 root tty       4,   8 Apr 24 13:23 tty8
crw--w----   1 root tty       4,   9 Apr 24 13:23 tty9
crw--w----   1 root tty     510,   0 Apr 24 13:23 ttyGS0
crw-------   1 root root      3,   0 Apr 24 13:23 ttyp0
crw-------   1 root root      3,   1 Apr 24 13:23 ttyp1
crw-------   1 root root      3,   2 Apr 24 13:23 ttyp2
crw-------   1 root root      3,   3 Apr 24 13:23 ttyp3
crw-------   1 root root      3,   4 Apr 24 13:23 ttyp4
crw-------   1 root root      3,   5 Apr 24 13:23 ttyp5
crw-------   1 root root      3,   6 Apr 24 13:23 ttyp6
crw-------   1 root root      3,   7 Apr 24 13:23 ttyp7
crw-------   1 root root      3,   8 Apr 24 13:23 ttyp8
crw-------   1 root root      3,   9 Apr 24 13:23 ttyp9
crw-------   1 root root      3,  10 Apr 24 13:23 ttypa
crw-------   1 root root      3,  11 Apr 24 13:23 ttypb
crw-------   1 root root      3,  12 Apr 24 13:23 ttypc
crw-------   1 root root      3,  13 Apr 24 13:23 ttypd
crw-------   1 root root      3,  14 Apr 24 13:23 ttype
crw-------   1 root root      3,  15 Apr 24 13:23 ttypf
crw--w----   1 root tty       4,  64 Apr 24 13:23 ttyS0
crw-rw----   1 root dialout   4,  65 Apr 24 13:23 ttyS1
crw-rw----   1 root dialout   4,  66 Apr 24 13:23 ttyS2
crw-rw----   1 root dialout   4,  67 Apr 24 13:23 ttyS3
crw--w----   1 root tty     238,   1 Apr 24 13:23 ttyTHS1
crw-rw----   1 root dialout 238,   2 Apr 24 13:23 ttyTHS2

.
.
Also, is the UART port UART0 or UART3? In the carrier board schematic I see it referenced as UART3 in the block diagram but the nets are named UART0.

Any help on would be greatly appreciated.

Thanks,
Jamie

hello JamieBasil,

it’s pin-99 and pin-101 routed to M.2 Key E connector on DevKit.
please check [Jetson Nano UART Pin Description] via Nano Product Design Guide for reference.
you may also download pinmux spreadsheets for reference, it’s Jetson Nano Signal Name using UART0, and its mapping to Ball Name, UART3.

so,
you’ll see this in the device tree blob,
for example,
$L4T_Sources/r32.5/Linux_for_Tegra/source/public/hardware/nvidia/platform/t210/porg/kernel-dts/tegra210-porg-p3448-common.dtsi

        serial@70006200 { /* UART-C : UART3 : M.2 Key E */
                compatible = "nvidia,tegra114-hsuart";
                dma-names = "tx";
                nvidia,adjust-baud-rates = <921600 921600 100>;
                status = "okay";
        };

Thanks @JerryChang. How do you access this UART3/C serial port? Do you know what tty device name it is?

hello JamieBasil,

please check kernel messages for the mapped port for using UART-C,
you may look for $ dmesg | grep THS, choose the port using 70006200.
for example,

$ dmesg | grep THS
[    1.106146] 70006040.serial: ttyTHS1 at MMIO 0x70006040 (irq = 64, base_baud = 0) is a TEGRA_UART
[    1.106537] 70006200.serial: ttyTHS2 at MMIO 0x70006200 (irq = 65, base_baud = 0) is a TEGRA_UART