Datasheet

Section 16 I
2
C Bus Interface (IIC) (Option)
Rev. 6.00 Mar. 18, 2010 Page 672 of 982
REJ09B0054-0600
16.4.7 IRIC Setting Timing and SCL Control
The interrupt request flag (IRIC) is set at different times depending on the WAIT bit in ICMR, the
FS bit in SAR, and the FSX bit in SARX. If the TDRE or RDRF internal flag is set to 1, SCL is
automatically held low after one frame has been transferred; this timing is synchronized with the
internal clock. Figure 16.19 shows the IRIC set timing and SCL control.
(a) When WAIT = 0, and FS = 0 or FSX = 0 (I
2
C bus format, no wait)
SCL
SDA
IRIC
User processing Write to ICDR (transmit)
or read ICDR (receive)
Clear IRIC
Clear
IRIC
Clear IRIC
1A8
1
1
A
7
1
2
2
2
2
2
2
8 97
(b) When WAIT = 1, and FS = 0 or FSX = 0 (I
2
C bus format, wait inserted)
SCL
SDA
IRIC
User processing
Clear
IRIC
Write to ICDR (transmit)
or read ICDR (receive)
SCL
SDA
IRIC
User processing
(c) When FS = 1 and FSX = 1 (synchronous serial format)
Write to ICDR (transmit)
or read ICDR (receive)
8
8 9
8
7
1
8
7
1
Figure 16.19 IRIC Setting Timing and SCL Control