XC908AS60ACFU Motorola Semiconductor Products, XC908AS60ACFU Datasheet - Page 518

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

Byte Data Link Controller (BDLC)
Technical Data
518
DLOOP — Digital Loopback Mode Bit
RX4XE — Receive 4X Enable Bit
NBFS — Normalization Bit Format Select Bit
This bit determines the source to which the digital receive input
(BDRxD) is connected and can be used to isolate bus fault conditions
(see
this control bit allows the programmer to connect the digital transmit
output to the digital receive input. In this configuration, data sent from
the transmit buffer will be reflected back into the receive buffer. If no
faults exist in the BDLC, the fault is in the physical interface block or
elsewhere on the J1850 bus.
This bit determines if the BDLC operates at normal transmit and
receive speed (10.4 kbps) or receive only at 41.6 kbps. This feature
is useful for fast download of data into a J1850 node for diagnostic or
factory programming of the node.
This bit controls the format of the normalization bit (NB). (See
27-18.) SAE J1850 strongly encourages using an active long (logic 0)
for in-frame responses containing cyclical redundancy check (CRC)
and an active short (logic 1) for in-frame responses without CRC.
1 = When set, BDRxD is connected to BDTxD. The BDLC is now
0 = When cleared, BDTxD is not connected to BDRxD. The BDLC
1 = When set, the BDLC is put in 4X receive-only operation.
0 = When cleared, the BDLC transmits and receives at 10.4 kbps.
1 = NB that is received or transmitted is a 0 when the response part
0 = NB that is received or transmitted is a 1 when the response part
Figure
in digital loopback mode.
is taken out of digital loopback mode and can now drive the
J1850 bus normally.
of an in-frame response (IFR) ends with a CRC byte. NB that
is received or transmitted is a 1 when the response part of an
in-frame response (IFR) does not end with a CRC byte.
of an in-frame response (IFR) ends with a CRC byte. NB that
is received or transmitted is a 0 when the response part of an
in-frame response (IFR) does not end with a CRC byte.
Byte Data Link Controller (BDLC)
27-13). If a fault condition has been detected on the bus,
MC68HC908AZ60A — Rev 2.0
MOTOROLA
Figure