R01UH0822EJ0100 Rev.1.00
Page 688 of 1041
Jul 31, 2019
RX13T Group
23. Serial Communications Interface (SCIg, SCIh)
Figure 23.55
Example of the Procedure for Master Reception Operations in Simple I
2
C Mode
(with Transmission Interrupts and Reception Interrupts in Use)
End
Initialization
Start of reception
[ 1 ]
No
Yes
STI interrupt?
[ 2 ]
Simultaneously set the SIMR3.IICSTAREQ bit
to 1 and the SIMR3.IICSCLS[1:0] and
IICSDAS[1:0] bits to 01b
Set the SIMR3.IICSTIF to 0, and set the
SIMR3.IICSCLS[1:0] and IICSDAS[1:0] bits to
00b
Write the slave address and value for
the R/W bit to TDR
No
Yes
No
Yes
SISR.IICACKR = 0?
[ 3 ]
Write FFh as dummy data to TDR
No
Yes
RXI interrupt?
No
Next data is the last?
No
Yes
STI interrupt?
Simultaneously set the SIMR3.IICSTPREQ
bit to 1 and the SIMR3.IICSCLS[1:0] and
IICSDAS[1:0] bits to 01b
Set the SIMR3.IICSTIF flag to 0, and set the
SIMR3.IICSCLS[1:0] and IICSDAS[1:0] bits to
11b
TXI interrupt?
[ 5 ]
[ 4 ]
[ 7 ]
Set SIMR2.IICACKT to 0
Set SCR.RIE to 1
Read received data from RDR
Yes
No
TXI interrupt?
Yes
Set SIMR2.IICACKT to 1
Write FFh as dummy data to TDR
No
RXI interrupt?
Read received data from RDR
Yes
No
TXI interrupt?
Yes
[ 6 ]
[ 1 ]
Initialization for simple I
2
C mode:
Set the RIE bit in SCR to 0.
[ 2 ]
Generate a start condition.
[ 3 ]
Writing to TDR:
Writing the slave address and value for the R/W bit to
TDR.
[ 4 ]
Confirming ACK response from the slave address:
Check the SISR.IICACKR bit. If its value is 0, it is indicated
that the slave device responded with ACK and operations
proceed. If its value is 1, it is indicated that there was no
response from a slave device so the next transition is to
generation of the stop condition.
[ 5 ]
Steps for continuing with reception:
To proceed with reception, write FFh as dummy transmit
data to TDR. Other than in the first and last rounds of
transmission, a TXI request can activate DTC to handle
writing of data to TDR. Furthermore, other than for the last
data to be received, an RXI request can activate the DTC
to handle reading of data from RDR.
[ 6 ]
NACK is transmitted in response to the last data.
[ 7 ]
Generation of a stop condition.
Note:
In simple I
2
C mode, the TXI interrupt request is generated when
communication is completed, unlike the timing during clock-
synchronous transmission.