[avr-chat] Re: Anyone used the XMega128A1 IrCOM module? Inverted output?

[Bob Paddock]

To follow up on this, the output is indeed inverted from what would be
considred normal
for IrDA SIR.

On Fri, May 22, 2009 at 12:07 PM, Bob Paddock <address@hidden> wrote:
> Anyone used the XMega128A1 IrCOM module?
>
> To me it seems that the output state of the module is inverted
> from what is normal for driving IrDA transceivers, like
> the Vishay TFDU4300.  This makes IrDA reception difficult.

avr(at)atmel.com wrote:
"Hi Bob,

The IRCOM module was not specifically developed to support IrDA tranceivers."

I find that statement bizarre.  Why would you use the IRCOM module
anyplace else?

"But this is easily accomplished by the invert functionality on the
pins that is not overridden by either the USART or the IRCOM.

To enable the inverted functionality of the pins, add:

PORTE.PIN2CTRL = PORT_INVEN_bm; /* This will invert the RX input. */

PORTE.PIN3CTRL = PORT_INVEN_bm; /* This will invert the TX output to
be active low. */"

Note that you only want Tx inverted, not Rx, so just add the last one on PIN3,
for a IrDA SIR transceiver.

I had the wrong pin in my original code to try to get Tx inverted.
I suggsted to avr(at)atmel.com that they document the required inversion.