Motorola MCF5281, MCF5282 24.5.2 I2C Frequency Divider Register I2FDR, 3describes I2FDRIC

Models: MCF5282 MCF5281

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Programming Model

24.5.2 I2C Frequency Divider Register (I2FDR)

The I2FDR, shown in Figure 24-6,provides a programmable prescaler to configure the I2C clock for bit-rate selection.

7

6

5

0

Field

Reset

R/W

Address

IC

 

 

0000_0000

R/W

IPSBAR + 0x304

Figure 24-6. I2C Frequency Divider Register (I2FDR)

Table 24-3describes I2FDR[IC].

Table 24-3. I2FDR Field Descriptions

Bits

Name

Description

 

 

 

7–6

Reserved, should be cleared.

 

 

 

5–0

IC

I2C 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

 

 

 

 

 

 

 

 

 

 

 

MOTOROLA

Chapter 24. I2C Interface

24-7

Page 517
Image 517
Motorola MCF5281, MCF5282 24.5.2 I2C Frequency Divider Register I2FDR, 3describes I2FDRIC, I2FDR Field Descriptions