Chapter 13 Inter-Integrated Circuit (MC9S12XDP512) Block Description
MC9S12XDP512 Data Sheet, Rev. 2.11
Freescale Semiconductor 597
13.3.2.2 IIC Frequency Divider Register (IBFD)
Read and write anytime

Table 13-2. IBAD Field Descriptions

Field Description
7:1
ADR[7:1]
Slave Address — Bit 1 to bit 7 contain the specific slave address to be used by the IIC bus module.The default
mode of IIC bus is slave mode for an address match on the bus.
0
Reserved
Reserved — Bit 0 of the IBAD is reserved for future compatibility. This bit will always read 0.
Offset Module Base + 0x0001
76543210
R
IBC7 IBC6 IBC5 IBC4 IBC3 IBC2 IBC1 IBC0
W
Reset 00000000
= Unimplemented or Reserved

Figure 13-4. IIC Bus Frequency Divider Register (IBFD)

Table 13-3. IBFD Field Descriptions

Field Description
7:0
IBC[7:0]
I Bus Clock Rate 7:0 — This field is used to prescale the clock for bit rate selection. The bit clock generator is
implemented as a prescale divider — IBC7:6, prescaled shift register — IBC5:3 select the prescaler divider and
IBC2-0 select the shift register tap point. The IBC bits are decoded to give the tap and prescale values as shown
in Table 13-4.

Table 13-4. I-Bus Tap and Prescale Values

IBC2-0
(bin)
SCL Tap
(clocks)
SDA Tap
(clocks)
000 5 1
001 6 1
010 7 2
011 8 2
100 9 3
101 10 3
110 12 4
111 15 4
IBC5-3
(bin)
scl2start
(clocks)
scl2stop
(clocks)
scl2tap
(clocks)
tap2tap
(clocks)
0002741
0012742