Toshiba TMP91C815F Data Book page 172

(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 the TMP91C815 is in
Master Mode.
Clear SBI0CR2<MST,TRX,BB> to 0 and set SBI0CR2<PIN> to 1 to release the bus. The SDA line
remains High and the SCL pin is released. Since a stop condition has not been generated on the bus,
other devices assume the bus to be in Busy state. Monitor the value of SBI0SR<BB> until it
becomes 0 so as to ascertain when the TMP91C815's SCL pin 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 remains in a free state, generate a start condition using the procedure
described in 3.10.6 (2).
In order to satisfy the set-up time requirements 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.
0 → <MST>
0 → <TRX>
0 → <BB>
1 → <PIN>
SCL line
Internal SCL
9
output
(TMP91C815)
SDA line
<LRB>
<BB>
<PIN>
Figure 3.10.19 Timing diagram for TMP91C815F Restart
1 → <MST>
1 → <TRX>
1 → <BB>
1 → <PIN>
4.7[µs] (Min.)
91C815-
169
TMP91C815
Start codnition