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

[Bob Paddock]

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.

For a point of reference take a look at figure 2-7
of the MCP2122 protocol converter:
http://ww1.microchip.com/downloads/en/DeviceDoc/21894c.pdf

All of the IrDA SIR Phy. devices I'm familiar with have the IrDA
Tx line as active *high* which means that it rests *low*, the
XMega is doing the opposite.

So that the SIR devices don't see their own transmission, they
hold their Rx line high any time Tx is high.  This means it is
impossible to receive anything, without resorting to screwing
with port direction control, which I've not tried yet.

I tried using the PORT_INVERT logic, but that doesn't
seem to work.  I'm guessing that is overridden
by the IrCOM module?

This is the code where I initialize PORTE for IrCOM.
IrCOM is not enabled on any other port.

   AVR_ENTER_CRITICAL_REGION();
   PORTE.DIRSET   = PIN3_bm;   /* PE3 (TXD0) as output */
   PORTE.DIRCLR   = PIN2_bm;   /* PE2 (RXD0) as input  */
   PORTE.PIN0CTRL = PORT_INVEN_bm; /* Fix IrCOM Bug? [Doesn't seem to
mater if this is here, overridden?] */

   PORTB.DIRSET   = PIN0_bm;   /* PB0 as output */
   PORTB.OUTCLR   = PIN0_bm;   /* PB0 Enable IrDA SD=Low=Active */

   /* Disable both RX and TX if already running: */
   USARTE0.CTRLB &= (uint8_t) ~(USART_RXEN_bm | USART_TXEN_bm);

   USART_Baudrate_Set(&USARTE0, 51 , 0); /* Baud Rate 38,400: BSel=51,
BScale=0, error %0.16 */

   /* USARTE0, 8 Data bits, No Parity, 1 Stop bit: */
   USART_Format_Set(&USARTE0, USART_CHSIZE_8BIT_gc,
USART_PMODE_DISABLED_gc, false);

   /* Set USARTE0 in IrDA mode.*/
   USART_SetMode(&USARTE0, USART_CMODE_IRDA_gc);
...

Have I missed something, or is the XMega IrCOM output improperly inverted?