MC68HC05BD3 Datasheet, PDF (52/112 Pages) Motorola, Inc – HCMOS microcontroller

7.3.1 M-Bus Address Register (MADR)
Address bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
$0017 MAD7 MAD6 MAD5 MAD4 MAD3 MAD2 MAD1
0000 0000
MAD1-MAD7 are the slave address bits of the M-Bus module.
7.3.2 M-Bus Frequency Register (MFDR)
Address bit 7
bit 6
bit 5
bit 4
bit 3
bit 2
bit 1
bit 0
State
on reset
$0018
FD4 FD3 FD2 FD1 FD0 0000 0000
FD0-FD4 are used for clock rate selection. The serial bit clock frequency is equal to the CPU clock
divided by the divider shown in Table 7-1.
7
Table 7-1 M-Bus Prescaler
FD4 FD3 FD2 FD1 FD0 DIVIDER FD4 FD3 FD2 FD1 FD0 DIVIDER
0
0
0
0
0
22
1
0
0
0
0
352
0
0
0
0
1
24
1
0
0
0
1
384
0
0
0
1
0
28
1
0
0
1
0
448
0
0
0
1
1
34
1
0
0
1
1
544
0
0
1
0
0
44
1
0
1
0
0
704
0
0
1
0
1
48
1
0
1
0
1
768
0
0
1
1
0
56
1
0
1
1
0
896
0
0
1
1
1
68
1
0
1
1
1
1088
0
1
0
0
0
88
1
1
0
0
0
1408
0
1
0
0
1
96
1
1
0
0
1
1536
0
1
0
1
0
112
1
1
0
1
0
1792
0
1
0
1
1
136
1
1
0
1
1
2176
0
1
1
0
0
176
1
1
1
0
0
2816
0
1
1
0
1
192
1
1
1
0
1
3072
0
1
1
1
0
224
1
1
1
1
0
3584
0
1
1
1
1
272
1
1
1
1
1
4352
For a 4MHz external crystal operation (2MHz internal operating frequency), the serial bit clock
frequency of M-Bus ranges from 460Hz to 90,909Hz.
MOTOROLA
7-6
M-BUS SERIAL INTERFACE
TPG
MC68HC05BD3