In uart example the protocol used is RS232?

[Pablo]

I program the uart example in my board nRF51 dk. I put a osciloscope in pin 9 and the signal is a square wave between 0 al 30V. So i think that the protocol is RS232, is this correct?

[Nguyen Hoan Hoang]

is your probe set to x10 ? You should see about 3V.

[Pablo]

Oh, maybe yes because sometimes the equipment in the school is not the best. But my question is about the protocol in the serial comunication. I don`t know if is a RS232 protocol or only TTL

[Nguyen Hoan Hoang]

It's logic level. To make it RS-232, yo need to add the MAX 232 chip

[awneil]

To be more precise, To make it RS-232, yo need to add an RS-232 transceiver.

The MAX 232 is just one example of an RS-232 transceiver - many, many alternatives are available.

[Sigurd]

No, RS232 is not used in the UART example, it uses TTL logic levels (0 - VDD).

With the RS-232 standard a logic high ('1') is represented by a negative voltage (from -3V to -25V), while a logic low ('0') is a positive voltage (from 3V to 25V). So if you want to use RS232, you need to add a RS232 transmitter/receiver, e.g. MAX232.