Renesas HD6417641 用户手册

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Section 16   I
2
C Bus Interface 2 (IIC2) 
 
 
Rev. 4.00  Sep. 14, 2005  Page 507 of 982 
 
 REJ09B0023-0400 
16.6 
Bit Synchronous Circuit 
In master mode, this module has a possibility that high level period may be short in the two states 
described below. 
•  When SCL is driven to low by the slave device 
•  When the rising speed of SCL is lowered by the load of the SCL line (load capacitance or pull-
up resistance) 
 
Therefore, it monitors SCL and communicates by bit with synchronization. 
Figure 16.22 shows the timing of the bit synchronous circuit and table 16.4 shows the time when 
SCL output changes from low to Hi-Z then SCL is monitored. 
SCL
V
IH
SCL monitor 
timing reference 
clock
Internal SCL
 
Figure 16.22   The Timing of the Bit Synchronous Circuit 
Table 16.4  Time for Monitoring SCL 
CKS3 
CKS2 
CKS2CYC 
Time for Monitoring SCL 
0 6.5 
pcyc 
1 5.5 
pcyc 
0 18.5 
pcyc 
1 17.5 
pcyc 
0 16.5 
pcyc 
1 15.5 
pcyc 
0 40.5 
pcyc 
1 39.5 
pcyc 
Note:  The pcyc indicates the peripheral clock cycle.