max232 pin states

I can't talk you through how it trickles down through the sewers of the Windows drivers, but once it gets to the MAX232, the first thing that happens is that the input R1in (if that's connected to the output of the UART) goes low for one bit period (i.e. 1/(Baud rate)). '1' is 0x31, high is a logic 1 and low is a logic 0 (it's inverted by the MAX232) and the data goes feet first, so the following 8 bit periods are high, low, low,high, high, low, low. Then the input goes high for at least 1 bit period.

This all assumes 8N1.

Paul Burke

If the RS-232 '1' input is -12V or so, you should get a logic high (+5V) out of the MAX232.

Leon