Re: RTS CTS Problem

the problem is that when I set the CTS AVR GPIO high(1) the voltage
that I see the 9 way connector pin is -5v and when  I set CTS AVR GPIO
to low(0) the voltage on the  9 way connector is 0v.

Is that the expected behavior? I think i am missing some fundamental
concept.

It is the expected behaviour allright if the buffers you use are
inverting (they normally are).
But you need to drive CTS _low_ to enable data flow, not high.
This is how all CTS inputs (past buffers, at TTL level) I have
seen work. :-)

Dimiter

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On Jan 30, 9:28 pm, ratemonotonic <niladri1...@xxxxxxxxx> wrote:
Hi all ,

I am using GPIO lines of an AVR to control the RTS & CTS lines of the
RS232 interface. The level convertor that I am using is MAX3222.

Software wise when the AVR is configured as a DCE so the RTS line is
input and CTS is output , the software sets the GPIO going to the CTS
high as long as it has buffer space , when it is wants the DTE to stop
sending data it pull the GPIO low.

the problem is that when I set the CTS AVR GPIO high(1) the voltage
that I see the 9 way connector pin is -5v and when  I set CTS AVR GPIO
to low(0) the voltage on the  9 way connector is 0v.

Is that the expected behavior? I think i am missing some fundamental
concept.

BR
rate

.