Modem Status Register (Fmsr) - Renesas H8S/2100 Series Hardware Manual

6-bit single-chip microcomputer

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Table of Contents

Section 16 Serial Communication Interface with FIFO (SCIF)

16.3.12 Modem Status Register (FMSR)

FMSR is a read-only register that indicates the status of or a change in the modem control pins.

Rev. 1.00 May 09, 2008 Page 472 of 954

REJ09B0462-0100

Initial Value R/W

Data Carrier Detect

Indicates the inverted state of the DCD input pin.

Ring Indicator

Indicates the inverted state of the RI input pin.

Data Set Ready

Indicates the inverted state of the DSR input pin.

Clear to Send

Indicates the inverted state of the CTS input pin.

Delta Data Carrier Indicator

Indicates a change in the DCD input signal after the

DDCD bit is read.

0: No change in the DCD input signal after FMSR

[Clearing condition]

1: A change in the DCD input signal after FMSR

[Setting condition]

A change in the DCD input signal

Trailing Edge Ring Indicator

Indicates a rise in the RI input signal after the TERI

bit is read.

0: No change in the RI input signal after FMSR

[Clearing condition]

1: A rise in the RI input signal after FMSR read

[Setting condition]

A rise in the RI input pin