Datasheet

Section 16 I

C Bus Interface [H8S/2138 Group Option]

Rev. 4.00 Jun 06, 2006 page 478 of 1004

REJ09B0301-0400

Bit 4

AASX Description

0 Second slave address not recognized (Initial value)

[Clearing conditions]

1. When 0 is written in AASX after reading AASX = 1

2. When a start condition is detected

3. In master mode

1 Second slave address recognized

[Setting condition]

When the second slave address is detected in slave receive mode while FSX = 0

Bit 3—Arbitration Lost (AL): This flag indicates that arbitration was lost in master mode. The

C bus interface monitors the bus. When two or more master devices attempt to seize the bus at

nearly the same time, if the I

C bus interface detects data differing from the data it sent, it sets AL

to 1 to indicate that the bus has been taken by another master.

AL is cleared by reading AL after it has been set to 1, then writing 0 in AL. In addition, AL is

reset automatically by write access to ICDR in transmit mode, or read access to ICDR in receive

mode.

Bit 3

AL Description

0 Bus arbitration won (Initial value)

[Clearing conditions]

1. When ICDR data is written (transmit mode) or read (receive mode)

2. When 0 is written in AL after reading AL = 1

1 Arbitration lost

[Setting conditions]

1. If the internal SDA and SDA pin disagree at the rise of SCL in master transmit

mode

2. If the internal SCL line is high at the fall of SCL in master transmit mode

Bit 2—Slave Address Recognition Flag (AAS): In I

C bus format slave receive mode, this flag is

set to 1 if the first frame following a start condition matches bits SVA6 to SVA0 in SAR, or if the

general call address (H'00) is detected.