UART protection

Q1: Are you in the US ? Q2: Which cell phone ?

don

you want to hook a micro that is known not to accept negative voltage to a phone that may or may not supply it. because you THINK that they have short circuit protection. Find out what you have and make the proper converter. if not one of the two will be toast.

serial

use

Hi Don,

A1: Yes A2: iPhone

I'll try and find an iPhone teardown to see what levels Apple use on the serial port. Just cant imagine they would level shift to try RS232 for the serial port but dont want to chance it.

Thanks

serial

use

Not quite. My goal is to educate myself about what is required for a serial connection instead of just resorting to a max232 solution.

Thanks

The microcontroller needs inverters for receive and transmit

Levels can simply be adapted with resistors and diodes.

E.g. 74HC00 nand as inverter in both lines. At the microcontroler end no protection, at the rs232 side at least a 1K resistor in series with each line and one or 2 diodes at the input of the nand gate.

best regards

Stefan DF9BI

Google found these:

This project will help you as well:

good luck

don