MPC5200B Users Guide, Rev. 1
20-8 Freescale Semiconductor
Memory Map and Registers
If the CPU executes a STOP all clocks to the BDLC as well as the clocks in the MCU are turned off including clocks to the BDLC.
The message which generates a Wake-up interrupt of the BDLC and the CPU will not be received correctly.
Symbol Invalid or Out of Range
CRC Error
The Cyclical Redundancy Check Byte is used by the receiver(s) of each message to determine if any errors have occurred during
the transmission of the message. If the message is not error free, the CRC error status is shown in the BDLC State Vector Register.
Loss of Arbitration
The Loss of Arbitration status is entered when a loss of arbitration occurs while the BDLC is transmitting onto the bus.
Tx Data Register Empty
The Tx Data Register Empty (TDRE) Byte is used to tell when data has been unloaded from the BDLC Data Register.
Rx Data Register Full
The Rx Data Register Full (RDRF) Byte is used to tell when data has been loaded in the BDLC Data Register.
Received IFR Byte
The BDLC can transmit and receive all four types of in-frame responses. As each byte of an IFR is received, the BDLC State Vector
Register indicates this by setting this state.
Received EOF
When a 280us passive period on the bus is received, it signifies an EOF. Whenever this occurs, the EOF flag is set.
No Interrupts Pending
This interrupt cannot generate an interrupt of the CPU.
20.7.3.3 BDLC Control Register 2 (DLCBCR2) - MBAR + 0x1304
This register controls transmitter operations of the BDLC module.
READ: any time
WRITE: any time
SMRST State Machine Reset (Bit 7)
The programmer can use this bit to reset the BDLC state machines to an initial state after the user put the off-chip analog transceiver in
loop back mode.
1 = Setting SMRST arms the state machine reset generation logic. Setting SMRST does not affect BDLC module behavior in any
way.
0 = Clearing SMRST after it has been set will cause the generation of a state machine reset. After SMRST is cleared, the BDLC
requires the bus to be idle for a minimum of an End of Frame symbol (EOF) time before allowing the reception of a message. The
BDLC requires the bus to be idle for a minimum of an Inter-Frame Separator symbol (IFS) time before allowing any message to be
transmitted.
DLOOP Digital Loopback Mode (Bit 6)
This bit determines the source to which the input of the digital filter is connected and can be used to isolate bus fault conditions. If a fault
condition has been detected on the bus, this control bit allows the programmer to disconnect the digital filter from input from the receive
pin (RXB) and connect it to the transmit output to the pin (TXB). In this configuration, data sent from the transmit buffer should be
reflected back into the receive buffer. If no faults exist in the digital block, the fault is in the physical interface block or elsewhere on the
J1850 bus.
1 = When set, digital filter input is connected to the transmitter output. The BDLC module is now in Digital Loopback Mode of
operation. The transmit pin (TXB) is driven low and not driven by the transmitter output.

Table20-4. BDLC Control Register 2

msb 01234567 lsb
R SMRST DLOOP 4XE NBFS TEOD TSIFR TMIFR1 TMIFR0
W
RESET:01000000