Is it possible to invert the serial logic on Teensy 3?

[pablotcarreira]

Hi, i'm trying to read a sensor who uses the SDI-12 protocol, it's a serial data 7E1 with negative logic.
I'm wondering if it's possible to set a register to invert the logic of the serial on the Teensy 3. I took a look at the MK20DX128 documentation but I didn't find that option.

Thanks.

 

[PaulStoffregen]

The hardware seems to support it.

Look at the RXINV bit in UARTx_S2 (section 45.3.6 on page 1061-1063) and the TXINV bit in UARTx_C3 (section 45.3.7 on page 1063-1065).

I have not personally tried using this feature, so I can't help... other than pointing you to these specific parts of the reference manual.

 

[PaulStoffregen]

Also, please pay attention to the text at the beginning of both of those sections, regarding the limitations as to when you may change those bits.

 

[pablotcarreira]

Thank you very much, I'll try to change it and then I'll post some feedback here.

 

[pablotcarreira]

It worked, I made UART0_C3 = 16 and the logic was inverted.

void setup()
{

delay(1000);
Serial.begin(9600); // USB is always 12 Mbit/sec
Serial1.begin(1200);
UART0_C3 = 16;

}

In the image it's possible to see in green an Arduino signal and in red the Teensy 3 inverted signal.