2–22

2.10 I2C Registers

2.10.1 I2CSTA: I2C Status and Control Register

This register is used to control the stop condition for read and write operation. In addition, it provides transmitter and

receiver handshake signals with their respective interrupt enable bits.

7

6

5

4

3

210

RXF

RIE

ERR

1/4

TXE

TIE

SRD

SWR

R/C

R/W

R/C

R/W

R/C

R/W

R/W

R/W

BIT

NAME

RESET

FUNCTION

0

SWR

0

Stop write condition. This bit defines if the I2C controller generates a stop condition when data from I2CDAO

register is transmitted to an external device.

SWR = 0

Stop condition is not generated when data from I2CDAO register is shifted out to an external

device.

SWR = 1

Stop condition is generated when data from I2CDAO register is shifted out to an external device.

1

SRD

0

Stop read condition. This bit defines if the I2C controller will generate a stop condition when data is received

and loaded into I2CDAI register.

SRD = 0

Stop condition is not generated when data from SDA line is shifted into I2CDAI register.

SRD = 1

Stop condition is generated when data from SDA line is shifted into I2CDAI register.

2

TIE

0

I2C transmitter empty interrupt enable.

TIE = 0 Interrupt disable

TIE = 1 Interrupt enable

3

TXE

1

I2C transmitter empty. This bit indicates that data can be written to the transmitter. It can be used for polling or

it can generate an interrupt.

TXE = 0

Transmitter is full. This bit is cleared when MCU writes a byte to I2CDAO register.

TXE = 1

Transmitter is empty. The I2C controller sets this bit when the content of I2CDAO register is

copied to the SDA shift–register.

4

1/4

0

Bus speed selection.

¼ = 0 > 100 kHz bus speed

¼ = 1 > 400 kHz bus speed

5

ERR

0

Bus error condition. This bit is set by the hardware when the device does not respond. It is cleared by the

MCU.

ERR = 0 No bus error

ERR = 1 Bus error condition has been detected. Clears when MCU writes a 1. Writing a 0 has no effect.

6

RIE

0

I2C receiver ready interrupt enable.

RIE = 0 Interrupt disable

RIE = 1 Interrupt enable

7

RXF

0

I2C receiver full. This bit indicates that the receiver contains new data. It can be used for polling or it can

generate an interrupt.

RXF = 0

Receiver is empty. This bit is cleared when MCU reads the I2CDAI register.

RXF = 1

Receiver contains new data. This bit is set by the I2C controller when the received serial data has

been loaded into I2CDAI register