LPC47M192 datasheet(71/228 Pages) SMSC

71 / 228 page

SMSC DS – LPC47M192

Page 71

Rev. 03/30/05

DATASHEET

Bit 7

This bit is permanently set to logic “0” in the 450 mode. In the FIFO mode, this bit is set to a logic “1” when there is at

least one parity error, framing error or break indication in the FIFO. This bit is cleared when the LSR is read if there

are no subsequent errors in the FIFO.

MODEM STATUS REGISTER (MSR)

Address Offset = 6H, DLAB = X, READ/WRITE

This 8 bit register provides the current state of the control lines from the MODEM (or peripheral device). In addition to

this current state information, four bits of the MODEM Status Register (MSR) provide change information. These bits

are set to logic “1” whenever a control input from the MODEM changes state. They are reset to logic “0” whenever

the MODEM Status Register is read.

Bit 0

Delta Clear To Send (DCTS). Bit 0 indicates that the nCTS input to the chip has changed state since the last time the

MSR was read.

Bit 1

Delta Data Set Ready (DDSR). Bit 1 indicates that the nDSR input has changed state since the last time the MSR

was read.

Bit 2

Trailing Edge of Ring Indicator (TERI). Bit 2 indicates that the nRI input has changed from logic “0” to logic “1”.

Bit 3

Delta Data Carrier Detect (DDCD). Bit 3 indicates that the nDCD input to the chip has changed state.

Note: Whenever bit 0, 1, 2, or 3 is set to a logic “1”, a MODEM Status Interrupt is generated.

Bit 4

This bit is the complement of the Clear To Send (nCTS) input. If bit 4 of the MCR is set to logic “1”, this bit is

equivalent to nRTS in the MCR.

Bit 5

This bit is the complement of the Data Set Ready (nDSR) input. If bit 4 of the MCR is set to logic “1”, this bit is

equivalent to DTR in the MCR.

Bit 6

This bit is the complement of the Ring Indicator (nRI) input. If bit 4 of the MCR is set to logic “1”, this bit is equivalent

to OUT1 in the MCR.

Bit 7

This bit is the complement of the Data Carrier Detect (nDCD) input. If bit 4 of the MCR is set to logic “1”, this bit is

equivalent to OUT2 in the MCR.

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