HC05 Datasheet, PDF (67/232 Pages) Motorola, Inc – High-density complementary metal oxide semiconductor (HCMOS) microcontroller unit

In a similar manner, the CPU module is notified that a message has been received only if it was
error free. If any error occurs, the MCAN signals the error within the CAN protocol without CPU
intervention.
The MCAN within the MC68HC05X16 is controlled using a block of 30 registers. This comprises
10 control registers, 10 Transmit buffer registers and 10 receive buffer registers. These registers
are memory mapped between $20 and $3D (see Figure 5-3).
Note:
There is an offset of $20 between the MC68HC05X16 addresses and the MCAN
internal addresses, i.e. MCAN addresses $00 to $1D, as defined in the BOSCH CAN
specification, are mapped to MC68HC05X16 addresses $20 to $3D.
MCAN register blocks
MCAN registers
5
$0020
$0029
$002A
$0033
$0034
$003D
MCAN
control registers
10 bytes
MCAN
transmit buffer
10 bytes
MCAN
receive buffer
10 bytes
Control register
Command register
Status register
Interrupt register
Acceptance code register
Acceptance mask register
Bus timing register 1
Bus timing register 2
Output control register
Test register
Identifier
RTR-bit, data length code
Data segment byte 1
Data segment byte 2
Data segment byte 3
Data segment byte 4
Data segment byte 5
Data segment byte 6
Data segment byte 7
Data segment byte 8
Identifier
RTR-bit, data length code
Data segment byte 1
Data segment byte 2
Data segment byte 3
Data segment byte 4
Data segment byte 5
Data segment byte 6
Data segment byte 7
Data segment byte 8
$0020
$0021
$0022
$0023
$0024
$0025
$0026
$0027
$0028
$0029
$002A
$002B
$002C
$002D
$002E
$002F
$0030
$0031
$0032
$0033
$0034
$0035
$0036
$0037
$0038
$0039
$003A
$003B
$003C
$003D
Figure 5-3 MCAN module memory map
MC68HC05X16
Rev. 1
MOTOROLA CAN MODULE (MCAN)
MOTOROLA
5-5