RX610 Group
22. I
2
C Bus Interface (RIIC)
R01UH0032EJ0120 Rev.1.20
Page 749 of 1006
Feb 20, 2013
22.7.2
Detection of the General Call Address
The RIIC has a facility for detecting the general call address (0000 000b + 0 [W]). This is enabled by setting the GCAE
bit in ICSER to 1.
If the address received after a start or restart condition is issued is 0000 000b + 1[R] (start byte), the RIIC recognizes this
as the address of a slave device with an "all-zero" address but not as the general call address.
When the RIIC detects the general call address, both the GCA flag in ICSR1 and the RDRF flag in ICSR2 are set to 1 on
the falling edge of the ninth cycle of SCL clock. This leads to the generation of a receive data full interrupt (ICRXI). The
value of the GCA flag can be confirmed to recognize that the general call address has been transmitted.
Operation after detection of the general call address is the same as normal slave receive operation.
AAS2
AAS0
S
2
3
4
5
6
7
0
0
0
0
0
0
1
AAS1
9
ACK
BBSY
RDRF
2
3
4
5
6
7
8
9
ACK
1
General call address match (0000 000b + W)
[General call address reception]
1
0
GCA
SCLn
SDAn
8
W
2
3
4
5
Read ICDRR
(Dummy read [7-bit address])
Read ICDRR
(DATA1)
Data (DATA1)
Data (DATA2)
Receive data (7-bit address)
Receive data (DATA1)
Figure 22.26 Timing of GCA Flag Setting to 1 during Reception of General Call Address