Functional Description
MPC5200B Users Guide, Rev. 1
Freescale Semiconductor 20-27
If a BREAK symbol is received while the BDLC module is transmitting or receiving, the symbol invalid or out of range flag (in
BDLC State Vector Register) is set. Further transmission/reception will be disabled until the J1850 bus returns to the passive state
and a valid EOF symbol is detected on the J1850 bus. If the interrupt enable bit (IE in BDLC Control Register 1) is set, an interrupt
request from the BDLC module is generated. Reading the BDLC State Vector Register register will clear this flag.
The BDLC module can transmit a BREAK symbol. And it can receive a BREAK symbol from the J1850 bus.
Bus Error Summary
The possible J1850 bus errors and the actions taken by the BDLC module are summarized in Table20-19.
20.8.2 Mux Interface
The MUX Interface is responsible for bit encoding/decoding and digital noise filtering between the Protocol Handler and the Physical
Interface. Refer to Figure20-2.

20.8.2.1 Mux Interface - Rx Digital Filter

The Receiver section of the BDLC module includes a digital low pass filter to remove narrow noise pulses from the incoming message. An
outline of the digital filter is shown in Figure 20-11.

Table20-19. BDLC module J1850 Error Summary

Error Condition BDLC Module Function
Transmission Error BDLC module will immediately cease transmitting. Further
transmission and reception will be disabled until a valid EOF symbol
is detected. The symbol invalid or out of range flag will be set and
interrupt generated if enabled.
Cyclical Redundancy Check (CRC)
Error
CRC error flag set and interrupt generated if enabled.
Symbol Error The symbol invalid or out of range flag will be set and interrupt
generated if enabled. Transmission and reception will be disabled
until a valid EOF symbol is detected.
Framing Error The symbol invalid or out of range flag will be set and interrupt
generated if enabled. Transmission and reception will be disabled
until a valid EOF symbol is detected.
Bus short to VDD. The BDLC module will not transmit until short is corrected and a
valid EOF is detected. Depending upon when short occurs and is
corrected, this error condition may set the symbol invalid or out of
range, crc error, or loss of arbitration flags.
Bus short to GND. Short will be seen as an idle bus by BDLC module. If a transmission
attempt is made before short is corrected, the symbol invalid or out
of range flag will be set and interrupt generated if enabled. Another
transmission can be initiated as soon as short is corrected.
BREAK symbol reception If doing so, the BDLC module will immediately cease transmitting.
Symbol invalid or out of range flag set and interrupt generated if
enabled.Transmission and reception will be disabled until a valid
EOF symbol is detected.