Datasheet

Section 16 I
2
C Bus Interface [Option]
Rev. 4.00 Sep 27, 2006 page 533 of 1130
REJ09B0327-0400
16.3.6 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 16.12 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 Clear IRIC Write to ICDR (transmit)
or read ICDR (receive)
1A8
1
1
A
7
1897
(b) When WAIT = 1, and FS = 0 or FSX = 0 (I
2
C bus format, wait inserted)
SCL
SDA
IRIC
User processing Clear
IRIC
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)
Clear IRIC Write to ICDR (transmit)
or read ICDR (receive)
8
89
8
7
1
8
7
1
Figure 16.12 IRIC Setting Timing and SCL Control