HardwareSerial.h begin()

[dtboy1995]

void begin(unsigned long baud, uint32_t config=SERIAL_8N1, int8_t rxPin=-1, int8_t txPin=-1, bool invert=false);

Can you explain the meaning of the last parameter invert for me.
Thanks.

[sysizlayan]

this is for voltage level conversion. 0V means 1, 3.3V means 0 if inverted.

[dtboy1995]

@sysizlayan thank you for your reply.
the default value is false, when will it be set to true ?
I don't quite understand.

[sysizlayan]

I have not used that flag also before but I believe it depends on the circuit topology to transmit and receive. For example, if you are using Schmidt Trigger, if you are using open drain/collector transistors or something similar to increase transmission power, this makes circuit simpler.

[dtboy1995]

thank you very much.

[stickbreaker]

The idle state of the serial is high(3.3v). A byte starts when the signal goes low(0v). Based on the programmed BAUD rate the hardware UART samples the signal level assigning the bit values. If invert is true, idle is low, a byte starts when the signal goes high, a high(3.3v) is interpreted as 0, low(0v) as 1.

Unless you have 'special' hardware connected, leave inverted false.

Chuck.

[dtboy1995]

@stickbreaker
thank you very much for your explanation!

[lbernstone]

Please close the issue.