MC68HC58 Motorola, MC68HC58 Datasheet - Page 61

• Manufacturer Part Number: MC68HC58
• Description: Data Link Controller
• Manufacturer: Motorola

MC68HC58
TECHNICAL DATA
For the DLC, status bytes and received data are transferred to the host MCU in pairs.
In serial mode, received data remains in the RxFIFO buffer until the host MCU sends
a “flush byte” command (data reads and flush commands can be executed at the same
time). In parallel mode, the host MCU first reads the status byte, and a subsequent
data read automatically flushes the data byte from the RxFIFO buffer.
Figures 4-11 and 4-12 outline the basic software requirements for retrieving data
which the DLC in serial mode has received from the J1850 multiplex bus.
• When the RxFIFO buffer has received 13 bytes.
• When a completion code is placed in the RxFIFO buffer.
• When a byte has been received into an empty RxFIFO buffer (optional).
Particular applications may require more extensive error monitoring
and handling routines than this flowchart displays. Conditions reflect-
ed in the retrieved status byte (TxFIFO status or J1850 bus status)
are also not addressed. Message filtering must be accomplished by
the software.
DATA LINK CONTROLLER OPERATION
NOTE
MOTOROLA
4-17