TMP91C824
91C824-165
When
the
<TRX>
is “0” (Receiver mode)
When the next transmitted data is 8 bits, write the transmitted data to SBI0DBR. When the next
transmitted data is other than 8 bits, set <BC2 to BC0> <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”. The TMP91C824F outputs a serial clock
pulse to the SCL to transfer new 1-word of data and sets the SDA pin to “0”, When the acknowledge
signal is set to Low-level at the final bit.
An INTS2 interrupt request then occurs and the <PIN> becomes “0”, Then the TMP91C824F pulls
down the SCL pin to the Low-level. The TMP91C824F outputs a clock pulse for 1-word of data
transfer and the acknowledge signal each time that received data is read from the SBI0DBR.
SCL line
D7
Acknowledge signal
to a transmitter
1
SDA line
2
3
4
5
6
7
8
9
D6
D5
D4
D3
D2
D1
<PIN>
INTS2
interrupt request
ACK
Output from Master
Output from Slave
D0
Read SBI0DBR
New D7
Figure 3.10.15
Example of when <BC2 to 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 <BC2 to BC0> to “001” and read the data. The TMP91C824F 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 TMP91C824F
generates a stop condition (see Section 3.10.6 (4)) and terminates data transfer.
SCL line
D7
Acknowledge signal
sent to a transmitter
1
SDA line
2
3
4
5
6
7
8
1
D6
D5
D4
D3
D2
D1
<PIN>
INTS2
interrupt request
output of Master
output of Slave
D0
“0”
→
<ACK>
Read SBI0DBR
“001”
→
<BC2 to 0>
Read SBI0DBR
Figure 3.10.16
Termination of data Transfer in Master Receiver Mode