Datasheet

PIC12(L)F1840
DS40001441D-page 232  2011-2013 Microchip Technology Inc.
25.5.7 CLOCK SYNCHRONIZATION AND
THE CKP BIT
Any time the CKP bit is cleared, the module will wait
for the SCL line to go low and then hold it. However,
clearing the CKP bit will not assert the SCL output low
until the SCL output is already sampled low. There-
fore, the CKP bit will not assert the SCL line until an
external I
2
C master device has already asserted the
SCL line. The SCL output will remain low until the CKP
bit is set and all other devices on the I
2
C bus have
released SCL. This ensures that a write to the CKP bit
will not violate the minimum high time requirement for
SCL (see Figure 25-23).
FIGURE 25-23: CLOCK SYNCHRONIZATION TIMING
SDA
SCL
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
SSP1CON1
CKP
Master device
releases clock
Master device
asserts clock