Freescale Semiconductor MPC5200B - Manual (Page 718)

Functional Description
MPC5200B Users Guide, Rev. 1
Freescale Semiconductor 20-39
• Transmitting a Type 1 IFR
To transmit a Type 1 IFR, the user loads the byte to be transmitted into the BDLC Data Register and sets both the TSIFR bit and the
TEOD bit. This will direct the BDLC module to attempt transmitting the byte written to the BDLC Data Register one time, preceded
by the appropriate Normalization Bit. If the transmission is not successful, the byte will be discarded and no further transmission
attempts will be made. For an illustration of the steps described below, refer to
Section Figure 20-15., Transmitting A Type 1 IFR .
• Step 1: Load the IFR Byte into the BDLC Data Register
The user begins initiation of a Type 1 IFR by loading the desired IFR byte into the BDLC Data Register. If a byte has already been
written into the BDLC Data Register for transmission as a new message, the user can simply write the IFR byte to the BDLC Data
Register, replacing the previously written byte. This must be done before the first EOD symbol is received.
• Step 2: Set the TSIFR and TEOD Bits
The final step in transmitting a Type 1 IFR with the BDLC module is to set the TSIFR and TEOD bits in BDLC Control Register
2. Setting both bits will direct the BDLC module to make one attempt at transmitting the byte in the BDLC Data Register as an IFR.
If the byte is transmitted successfully, or if an error or loss of arbitration occurs, TEOD and TSIFR will be cleared and no further
transmit attempts will be made.
• Transmitting a Type 2 IFR
To transmit a Type 2 IFR, the user loads the byte to be transmitted into the BDLC Data Register and sets the TSIFR bit. Once this
is done, the BDLC module will attempt to transmit the byte in the BDLC Data Register as a single byte IFR, preceded by the
appropriate Normalization Bit. If the first BDLC module loses arbitration on the first attempt, it will make repeated attempts to
transmit this byte until it is successful, an error occurs or the user sets the TEOD bit.