R01UH0823EJ0100 Rev.1.00
Page 1095 of 1823
Jul 31, 2019
RX23W Group
33. Serial Communications Interface (SCIg, SCIh)
33.12.4
Interrupts in Simple I
2
C Mode
The interrupt sources in simple I
2
C mode are listed in
. The STI interrupt is allocated to the transmit end
interrupt (TEI) request. The receive error interrupt (ERI) request cannot be used.
The DTC or DMAC can also be used to handle transfer in simple I
2
C mode.
When the value of the IICINTM bit in the SIMR2 register is 1, an RXI request will be generated on the falling edge of
the SSCLn signal for the eighth bit. If the RXI has been set up as an activating request for the DTC or DMAC
beforehand, the RXI request will activate the DTC or DMAC to handle transfer of the received data. Furthermore, a TXI
request is generated on the falling edge of the SSCLn signal for the ninth bit (acknowledge bit). If the TXI has been set
up as an activating request for the DTC or DMAC beforehand, the TXI request will activate the DTC or DMAC to
handle transfer of the transmit data.
When the value of the IICINTM bit in the SIMR2 register is 0, an RXI request (ACK detection) if the input on the
SSDAn pin is at the low level or a TXI request (NACK detection) if the input on the SSDAn pin is at the high level will
be generated on the rising edge of the SSCLn signal for the ninth bit (acknowledge bit). If the RXI has been set up as an
activating request for the DTC or DMAC beforehand, the RXI request will activate the DTC or DMAC to handle transfer
of the received data.
Also, if the DTC or DMAC is used for data transfer in reception or transmission, be sure to set up and enable the DTC or
DMAC before setting up the SCI.
When the IICSTAREQ, IICRSTAREQ, and IICSTPREQ bits in the SIMR3 register are used to generate a start condition,
restart condition, or stop condition, the STI request is issued when generation is complete.
Table 33.33
SCI Interrupt Sources
Note 1. Activation of the DTC or DMAC is only possible when the SIMR2.IICINTM bit is 1 (use reception and transmission interrupts).
Name
Interrupt Source
Interrupt Flag
DTC Activation
DMAC Activation
IICINTM bit = 0
IICINTM bit = 1
RXI
ACK detection
Reception
—
Possible
Possible
TXI
NACK detection
Transmission
—
Possible*
Possible*
STI
Completion of generation of a start,
restart, or stop condition
IICSTIF
Not possible
Not possible