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TMP92CM22
2007-02-16
92CM22-189
(5) Restart
Restart is used during data transfer between a master device and a slave device to
change the data transfer direction. The following description explains how to restart
when this device is in the master mode.
Clear the SBI0CR2<MST, TRX, BB> to “000” and set the SBI0CR2<PIN> to “1” to
release the bus. The SDA line remains the high level and the SCL pin is released. Since
a stop condition is not generated on the bus, other devices assume the bus to be in a
busy state. Check the SBI0SR<BB> until it becomes “0” to check that the SCL pin of
this device is released. Check the <LRB> until it becomes 1 to check that the SCL line
on a bus is not pulled down to the low level by other devices. After confirming that the
bus stays in a free state, generate a start condition with procedure described in
3.10.6
(2).
In order to meet setup time when restarting, take at least 4.7 μs of waiting time by
software from the time of restarting to confirm that the bus is free until the time to
generate the start condition.
Figure 3.10.19 Timing Diagram when Restarting
<LRB>
SCL (bus)
SCL pin
SDA pin
<PIN>
4.7 μs (Min)
<BB>
Start condition
“0” → <MST>
“0” → <TRX>
“0” → <BB>
“1” → <PIN>
“1” → <MST>
“1” → <TRX>
“1” → <BB>
“1” → <PIN>
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