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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

C Mode

The interrupt sources in simple I

C mode are listed in Table 33.33. 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

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 ActivationIICINTM 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

Renesas RX Series User Manual

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