XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 510

• Manufacturer Part Number: XC908AS60ACFU
• Description: MC68HC908AZ60A, MC68HC908AS60A Hcmos Microcontroller Unit Technical Data
• Manufacturer: Motorola Semiconductor Products

Byte Data Link Controller (BDLC)
Technical Data
510
Symbol Error
Framing Error
Bus Fault
any single and 2-bit errors, as well as all 8-bit burst errors and almost
all other types of errors. The CRC error flag ($18 in BSVR) is set when
a CRC error is detected. (See
A symbol error is detected when an abnormal (invalid) symbol is
detected in a message being received from the J1850 bus. However,
if the BDLC is transmitting when this happens, it will be treated as a
loss of arbitration ($14 in BSVR) rather than a transmitter error. The
($1C) symbol invalid or the out-of-range flag is set when a symbol
error is detected. Therefore, ($1C) symbol invalid flag is stacked
behind the ($14) LOA flag during a transmission error process. (See
BDLC State Vector
A framing error is detected if an EOD or EOF symbol is detected on a
non-byte boundary from the J1850 bus. A framing error also is
detected if the BDLC is transmitting the EOD and instead receives an
active symbol. The ($1C) symbol invalid or the out-of-range flag is set
when a framing error is detected. (See
Register.)
If a bus fault occurs, the response of the BDLC will depend upon the
type of bus fault.
If the bus is shorted to battery, the BDLC will wait for the bus to fall to
a passive state before it will attempt to transmit a message. As long
as the short remains, the BDLC will never attempt to transmit a
message onto the J1850 bus.
If the bus is shorted to ground, the BDLC will see an idle bus, begin
to transmit the message, and then detect a transmission error ($1C in
BSVR), since the short to ground would not allow the bus to be driven
to the active (dominant) SOF state. The BDLC will abort that
transmission and wait for the next CPU command to transmit.
In any case, if the bus fault is temporary, as soon as the fault is
cleared, the BDLC will resume normal operation. If the bus fault is
permanent, it may result in permanent loss of communication on the
J1850 bus. (See
Byte Data Link Controller (BDLC)
BDLC State Vector
Register.)
BDLC State Vector
Register.)
BDLC State Vector
MC68HC908AZ60A — Rev 2.0
Register.)
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