Toshiba TLCS-900/L1 Series Manual page 170

When the <TRX> is 0 (Receiver mode)
When the next transmitted data is other than 8 bits, set <BC2:0> <ACK> and
read the received data from SBI0DBR to release the SCL line (data which is read
immediately after a slave address is sent is undefined). After the data is read,
<PIN> becomes 1. Serial clock pulse for transferring new 1 word of data is
defined SCL and outputs "L" level from SDA pin with acknowledge timing.
An INTSBI interrupt request then occurs and the <PIN> becomes 0, Then the
TMP91C824FG pulls down the SCL pin to the low level. The TMP91C824
outputs a clock pulse for 1 word of data transfer and the acknowledge signal each
time that received data is read from the SBI0DBR.
Read SBI0DBR
SCL line 1
SDA line D7
<PIN>
INTSBI
interrupt request
Output from master
Output from slave
Figure 3.10.15 Example of when <BC2:0> = 000, <ACK> = 1 in Receiver Mode
In order to terminate the transmission of data to a transmitter, clear <ACK>
to 0 before reading data which is 1 word before the last data to be received. The
last data word does not generate a clock pulse as the acknowledge signal. After
the data has been transmitted and an interrupt request has been generated, set
BC<2:0> to 001 and read the data. The TMP91C824 generates a clock pulse for a
1-bit data transfer. Since the master device is a receiver, the SDA line on the bus
remains high. The transmitter interprets the high signal as an ACK signal. The
receiver indicates to the transmitter that data transfer is complete.
After the one data bit has been received and an interrupt request been
generated, the TMP91C824 generates a stop condition (See Section 3.10.6 (4))
and terminates data transfer.
SCL line
SDA line D7
<PIN>
INTSBI
interrupt request
0 → <ACK>
Read SBI0DBR
Output of master
Output of slave
Figure 3.10.16 Termination of Data Transfer in Master Receiver Mode
2 3 4
D6 D5 D4
1 2 3 4
D6 D5 D4
91C824-168
5 6 7 8
D3 D2 D1 D0
5 6 7
D3 D2 D1
TMP91C824
9
ACK New D7
Acknowledge signal
to a transmitter
8 1
D0
Acknowledge signal
sent to a transmitter
001 → <BC2:0>
Read SBI0DBR
2008-02-20