max232 pin states

[DigitalBug]

Hii

i feel stupid when i think what really happens at the r1out of max232
when i send "1" by means of a vb program, out of rs232 into r1in of
max232. any help will be appreciated.

 

[Paul Burke]

DigitalBug wrote:

Hii

i feel stupid when i think what really happens at the r1out of max232
when i send "1" by means of a vb program, out of rs232 into r1in of
max232. any help will be appreciated.

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

 

[Leon Heller]

"DigitalBug" <sharaf_cool@yahoo.co.in> wrote in message
news:1106034746.120226.220860@f14g2000cwb.googlegroups.com...

Hii

i feel stupid when i think what really happens at the r1out of max232
when i send "1" by means of a vb program, out of rs232 into r1in of
max232. any help will be appreciated.

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

Leon