Toshiba TLCS-900/L1 Series Manual page 173

(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 TMP91C824 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
TMP91C824'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 setup 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
(TMP91C824)
SDA line
<LRB>
<BB>
<PIN>
Figure 3.10.19 Timing Diagram for TMP91C824FG Restart
1 → <MST>
1 → <TRX>
1 → <BB>
1 → <PIN>
4.7 [µs] (Min)
91C824-171
TMP91C824
Start codnition
2008-02-20