Freescale Semiconductor MCF5480 - Manual (Page 858)

MCF548x Reference Manual, Rev. 3
28-4 Freescale Semiconductor
28.3.2.2 I
2
C Frequency Divider Register (I2FDR)
The I2FDR, shown in Figure 28-3 , provides a programmable prescaler to configure the I
2
C clock for
bit-rate selection.
7 6 5 4 3 2 1 0
R 0 0 IC
W
Reset 0 0 0 0 0 0 0 0
Reg
Addr
MBAR + 0x8F04
Figure 28-3. I
2
C Frequency Divider Register (I2FDR)
Table 28-4. I2FDR Field Descriptions
Bits Name Description
7–6 — Reserved, should be cleared.
5–0 IC I
2
C clock rate. Prescales the clock for bit-rate selection. Due to potentially slow SCL and SDA rise
and fall times, bus signals are sampled at the prescaler frequency. The serial bit clock frequency is
equal to the system clock divided by the divider shown below.
IC Divider IC Divider IC Divider IC Divider
0x00 28 0x10 288 0x20 20 0x30 160
0x01 30 0x11 320 0x21 22 0x31 192
0x02 34 0x12 384 0x22 24 0x32 224
0x03 40 0x13 480 0x23 26 0x33 256
0x04 44 0x14 576 0x24 28 0x34 320
0x05 48 0x15 640 0x25 32 0x35 384
0x06 56 0x16 768 0x26 36 0x36 448
0x07 68 0x17 960 0x27 40 0x37 512
0x08 80 0x18 1152 0x28 48 0x38 640
0x09 88 0x19 1280 0x29 56 0x39 768
0x0A 104 0x1A 1536 0x2A 64 0x3A 896
0x0B 128 0x1B 1920 0x2B 72 0x3B 1024
0x0C 144 0x1C 2304 0x2C 80 0x3C 1280
0x0D 160 0x1D 2560 0x2D 96 0x3D 1536
0x0E 192 0x1E 3072 0x2E 112 0x3E 1792
0x0F 240 0x1F 3840 0x2F 128 0x3F 2048