H8SSLASH2214 datasheet(581/936 Pages) RENESAS

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Section 12 Serial Communication Interface (SCI)

Rev.4.00 Sep. 18, 2008 Page 521 of 872

REJ09B0189-0400

Table 12.14 State of SSR Status Flags and Transfer of Receive Data

SSR Status Flags

RDRF

ORER

FER

PER

Receive Data Transfer

RSR to RDR

Receive Error Status

Overrun error

Framing error

Parity error

Overrun error + framing error

Overrun error + parity error

Framing error + parity error

Overrun error + framing error +

parity error

Legend:

: Receive data is transferred from RSR to RDR.

Receive data is not transferred from RSR to RDR.

(4) Break Detection and Processing (Asynchronous Mode Only)

When framing error (FER) detection is performed, a break can be detected by reading the RxD pin

value directly. In a break, the input from the RxD pin becomes all 0s, and so the FER flag is set,

and the parity error flag (PER) may also be set.

Note that, since the SCI continues the receive operation after receiving a break, even if the FER

flag is cleared to 0, it will be set to 1 again.

(5) Sending a Break (Asynchronous Mode Only)

The TxD pin has a dual function as an I/O port whose direction (input or output) is determined by

DR and DDR. This can be used to send a break.

Between serial transmission initialization and setting of the TE bit to 1, the mark state is replaced

by the value of DR (the pin does not function as the TxD pin until the TE bit is set to 1).

Consequently, DDR and DR for the port corresponding to the TxD pin are first set to 1.

To send a break during serial transmission, first clear DR to 0, then clear the TE bit to 0.

When the TE bit is cleared to 0, the transmitter is initialized regardless of the current transmission

state, the TxD pin becomes an I/O port, and 0 is output from the TxD pin.

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