Datasheet

Section 18 I

C Bus Interface [Option]

(This function is not available in the H8S/2695)

R01UH0166EJ0600 Rev. 6.00 Page 853 of 1434

Mar 02, 2011

H8S/2633 Group, H8S/2633 F-ZTAT

H8S/2633R F-ZTAT

, H8S/2695

Bit 3

ACKE Description

0 The value of the acknowledge bit is ignored, and continuous transfer

is performed (Initial value)

1 If the acknowledge bit is 1, continuous transfer is interrupted

Bit 2—Bus Busy (BBSY): The BBSY flag can be read to check whether the I

C bus (SCL, SDA)

is busy or free. In master mode, this bit is also used to issue start and stop conditions.

A high-to-low transition of SDA while SCL is high is recognized as a start condition, setting

BBSY to 1. A low-to-high transition of SDA while SCL is high is recognized as a stop condition,

clearing BBSY to 0.

To issue a start condition, use a MOV instruction to write 1 in BBSY and 0 in SCP. A retransmit

start condition is issued in the same way. To issue a stop condition, use a MOV instruction to

write 0 in BBSY and 0 in SCP. It is not possible to write to BBSY in slave mode; the I

C bus

interface must be set to master transmit mode before issuing a start condition. MST and TRS

should both be set to 1 before writing 1 in BBSY and 0 in SCP.

Bit 2

BBSY Description

0 Bus is free (Initial value)

[Clearing condition]

When a stop condition is detected

1 Bus is busy

[Setting condition]

When a start condition is detected