H8SSLASH2224 datasheet(768/1071 Pages) RENESAS

768 / 1071 page

Section 16 I

2C Bus Interface (IIC) (Option)

Rev. 5.00 Aug 08, 2006 page 682 of 982

REJ09B0054-0500

9. Notes on I2C Bus Interface Stop Condition Instruction Issuance

If the rise time of the 9th SCL acknowledge exceeds the specification because the bus load

capacitance is large, or if there is a slave device of the type that drives SCL low to effect a

wait, issue the stop condition instruction after reading SCL and determining it to be low, as

shown below.

Stop condition

SCL

IRIC

[1] Determination of SCL = low

9th clock

VIH

High period secured

[2] Stop condition instruction issuance

SDA

As waveform rise is late,

SCL is detected as low

Figure 16.23 Timing of Stop Condition Issuance

10. Notes on IRIC Flag Clearance when Using Wait Function

If the SCL rise time exceeds the designated duration or if the slave device is of the type that

keeps SCL low and applies a wait state when the wait function is used in the master mode of

the I2C bus interface, read SCL and clear the IRIC flag after determining that SCL has gone

low, as shown below.

Clearing the IRIC flag to 0 when WAIT is set to 1 and SCL is being held at high level can

cause the SDA value to change before SCL goes low, resulting in a start condition or stop

condition being generated erroneously.

SCL

SCL = high duration

maintained

[1] Judgement that SCL = low [2] IRIC clearance

VIH

SDA

IRIC

SCL = low detected

Figure 16.24 IRIC Flag Clearance in WAIT = 1 Status

H8S/2224 Scheda tecnica(PDF) 768 Page - Renesas Technology Corp