13.3.3IIC Control Register (IICC1)

R

W

Reset

7

6

5

 

4

3

2

1

0

IICEN

IICIE

MST

 

TX

TXAK

0

0

0

 

 

 

 

 

RSTA

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

0

0

0

 

0

0

0

0

0

 

= Unimplemented or Reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Figure 13-5. IIC Control Register (IICC1)

 

 

Table 13-6. IICC1 Field Descriptions

 

 

 

Field

 

Description

 

 

7

IIC Enable. The IICEN bit determines whether the IIC module is enabled.

IICEN

0

IIC is not enabled

 

1

IIC is enabled

 

 

6

IIC Interrupt Enable. The IICIE bit determines whether an IIC interrupt is requested.

IICIE

0

IIC interrupt request not enabled

 

1

IIC interrupt request enabled

 

 

5

Master Mode Select. The MST bit changes from a 0 to a 1 when a start signal is generated on the bus and master

MST

mode is selected. When this bit changes from a 1 to a 0 a stop signal is generated and the mode of operation

 

changes from master to slave.

 

0

Slave mode

 

1

Master mode

 

 

4

Transmit Mode Select. The TX bit selects the direction of master and slave transfers. In master mode, this bit

TX

should be set according to the type of transfer required. Therefore, for address cycles, this bit is always high.

 

When addressed as a slave, this bit should be set by software according to the SRW bit in the status register.

 

0

Receive

 

1

Transmit

 

 

3

Transmit Acknowledge Enable. This bit specifies the value driven onto the SDA during data acknowledge cycles

TXAK

for master and slave receivers.

 

0

An acknowledge signal is sent out to the bus after receiving one data byte

 

1

No acknowledge signal response is sent

 

 

2

Repeat start. Writing a 1 to this bit generates a repeated start condition provided it is the current master. This bit

RSTA

is always read as cleared. Attempting a repeat at the wrong time results in loss of arbitration.

 

 

 

MCF51QE128 MCU Series Reference Manual, Rev. 3

Freescale Semiconductor

2-267

Page 267
Image 267
Freescale Semiconductor MCF51QE128RM manual IIC Control Register IICC1, IICC1 Field Descriptions