MC68908GZ8MFJE Datasheet, PDF (125/314 Pages) Freescale Semiconductor, Inc – Microcontrollers

MSCAN08
RxBG
RxFG
RXF
Message Storage
CPU08 I BUS
Tx0
TXE
PRIO
Tx1
TXE
PRIO
Tx2
TXE
PRIO
Figure 12-3. User Model for Message Buffer Organization
12.4.3 Transmit Structures
The MSCAN08 has a triple transmit buffer scheme to allow multiple messages to be set up in advance
and to achieve an optimized real-time performance. The three buffers are arranged as shown in
Figure 12-3.
All three buffers have a 13-byte data structure similar to the outline of the receive buffers (see 12.12
Programmer’s Model of Message Storage). An additional transmit buffer priority register (TBPR) contains
an 8-bit “local priority” field (PRIO) (see 12.12.5 Transmit Buffer Priority Registers).
MC68HC908GZ16 • MC68HC908GZ8 Data Sheet, Rev. 4
Freescale Semiconductor
125