© 2000 Ubicom, Inc. All rights reserved. - 7 - www.ubicom.com SX IrDA Virtual Peripheral Implementation AN16 3.2.5   Transmit API The  pl2flTxStart  call  starts  the  transmission  of  a  frame
header immediately and resets the receive state to idle.
When  the  framing  layer  can  transmit  a  payload  byte  it
calls fl2plTxData to obtain the data to transmit. The pay-
load byte is returned in w and the z flag is set if this is the last byte to be sent. This process will be repeated until a
last indication is detected.
Finally  fl2plTxComplete  is  called  once  the  frame  has
been  completely  sent  (i.e.  the  stop  bit  of  the  EOF  byte
has been sent). 3.2.6   Transmit State Machine Table 3-2 shows the Framing Layer Transmit State Machine Control RxAvail = BOF Indicate data error to payload layer (fl2plRxError). Begin RxAvail = EOF XOR RxData with $20.
Add to FCS.
Pass to payload layer via FIFO buffer. Idle RxAvail = Other Payload All States pl2flRxIgnore Idle RxAvail = EOF & FCS = valid Indicate data error to payload layer (fl2plRxError). Idle RxAvail = EOF & FCS = invalid Idle RxAvail = CE Add data to FCS
Pass RxData to payload layer via FIFO buffer. Control RxAvail = Other Indicate data error to payload layer (fl2plRxError). Payload Table 3-1.   Framing Layer Receive State Machine pl2flTxStarT () The payload layer wants to transmit a frame. fl2plTxData (ret w=Data, z=Last) Request the next payload byte. fl2plTxComplete () The frame has been completely sent. Figure 3-3.  Framing Layer Transmit API Table 3-2.   Framing Layer Transmit State Machine Current State Event Action Next State Idle pl2flTxStart () Initialize FF counter.
Send FF byte. Begin Begin TxEmpty & Counter-- <> 0 Send FF byte. Begin TxEmpty & Counter-- = 0 Initialize FCS.
Send BOF byte. Payload