M68HC12A4EVB Freescale Semiconductor, M68HC12A4EVB Datasheet - Page 257

• Manufacturer Part Number: M68HC12A4EVB
• Manufacturer: Freescale Semiconductor

Specifications of M68HC12A4EVB

• Lead Free Status / Rohs Status: Not Compliant

16.10 Memory Map
The msCAN12 occupies 128 bytes in the CPU12 memory space. The background receive buffer can be
read only in test mode.
16.11 Programmer’s Model of Message Storage
This subsection details the organization of the receive and transmit message buffers and the associated
control registers.
16.11.1 Message Buffer Organization
Figure 16-10
simplification, the receive and transmit message buffers have the same register organization. Each
message buffer allocates 16 bytes in the memory map containing:
All bits of the 13-byte data structure are undefined out of reset.
Freescale Semiconductor
•
•
•
13-byte data structure which includes an identifier section (IDRn), a data section (DSRn), and the
data length register (DLR)
Transmit buffer priority register (TBPR) which is only applicable for transmit buffers. See
Transmit Buffer Priority Register
Two unused bytes
shows the organization of a single message buffer. For reasons of programmer interface
The receive buffer can be read anytime but cannot be written. The transmit
buffers can be read or written anytime.
Figure 16-9. msCAN12 Memory Map
$010D
$013C
$013D
$010E
M68HC12B Family Data Sheet, Rev. 9.1
$010F
$011F
$013F
$014F
$015F
$016F
$017F
$0100
$0108
$0109
$0110
$0120
$0140
$0150
$0160
$0170
TRANSMIT BUFFER 0 (Tx0)
TRANSMIT BUFFER 1 (Tx1)
TRANSMIT BUFFER 2 (Tx2)
RECEIVE BUFFER (RxFG)
PORT CAN REGISTERS
CONTROL REGISTERS
NOTE
ERROR COUNTERS
IDENTIFIER FILTER
RESERVED
RESERVED
16 BYTES
29 BYTES
9 BYTES
5 BYTES
2 BYTES
3 BYTES
Memory Map
16.11.5
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