fix(kakuteh7.default.px4board): remove CONFIG_BOARD_SERIAL_TEL2

[iftahnaf]

Solved Problem

From the documentation, Kakute H7 does not have the TELEM2 option. It does appear in the default.px4board file:

PX4-Autopilot/boards/holybro/kakuteh7/default.px4board

Line 5 in f7e6e13

CONFIG_BOARD_SERIAL_TEL2="/dev/ttyS1"

Solution

The simple solution is to remove the line from the file so it won't appear as an option.

Alternatives

We could also disable serial console and use R3/T3 pins as TELEM2:

1. Disable the serial console:
   

   PX4-Autopilot/boards/holybro/kakuteh7/nuttx-config/nsh/defconfig

   Line 240 in f7e6e13

   CONFIG_USART3_SERIAL_CONSOLE=y

2. Change the CONFIG_BOARD_SERIAL_TEL2 in the default.px4board to the correct UART (from the documentation:

CONFIG_BOARD_SERIAL_TEL2="/dev/ttyS2"

@vincentpoont2 I would appreciate it if you could review this.

[beniaminopozzan]

side question: is /dev/ttyS1 the one referred to as UART 2 in the Holybro documentation?

[iftahnaf]

I'm not sure, but I guess so; I couldn't get a clear answer from Holybro's tech support.

[vincentpoont2]

@iftahnaf Thanks for the suggestion.
KakuteH7's Telem2 is connected to the UART of the Bluetooth chip via a resistor inside the board, but it has no exposed solder pad.

Although it is not exposed by default. There are workaround, so I think it's better to keep this line of config.
The workaround is as follow:

There might a version in the future that doesn't have bluetooth and exposed the UART2.

[vincentpoont2]

side question: is /dev/ttyS1 the one referred to as UART 2 in the Holybro documentation?

-----Yes, dev/ttys1 corresponds to UART2
-----The UART correspondence of PX4 is ttys0->UART1, ttys1->UART2, ttys2->UART3, and so on

[iftahnaf]

@vincentpoont2 Awesome, thanks for the clarification.
I'll add this to the PX4 Kakute H7 docs.