Datasheet

PIC18F45J10 FAMILY
DS39682E-page 172 © 2009 Microchip Technology Inc.
16.4.4.5 Clock Synchronization and
the CKP bit
When the CKP bit is cleared, the SCLx output is forced
to ‘0’. However, clearing the CKP bit will not assert the
SCLx output low until the SCLx output is already sam-
pled low. Therefore, the CKP bit will not assert the
SCLx line until an external I
2
C master device has
already asserted the SCLx line. The SCLx output will
remain low until the CKP bit is set and all other
devices on the I
2
C bus have deasserted SCLx. This
ensures that a write to the CKP bit will not violate the
minimum high time requirement for SCLx (see
Figure 16-12).
FIGURE 16-12: CLOCK SYNCHRONIZATION TIMING
SDAx
SCLx
DX – 1DX
WR
Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4 Q1 Q2 Q3 Q4
SSPxCON
CKP
Master Device
Deasserts Clock
Master Device
Asserts Clock