sc16c852viet NXP Semiconductors, sc16c852viet Datasheet - Page 31

• Manufacturer Part Number: sc16c852viet
• Description: Sc16c852v 1.8 V Dual Uart, 5 Mbit/s Max. With 128-byte Fifos, Infrared Irda , And Xscale Vlio Bus Interface
• Manufacturer: NXP Semiconductors

NXP Semiconductors
SC16C852V_4
Product data sheet
7.8 Modem Status Register (MSR)
This register shares the same address as EFCR register. This is a read-only register and
it provides the current state of the control interface signals from the modem, or other
peripheral device to which the SC16C852V is connected. Four bits of this register are
used to indicate the changed information. These bits are set to a logic 1 whenever a
control input from the modem changes state. These bits are set to a logic 0 whenever the
CPU reads this register.
When write, the data will be written to EFCR register.
Table 23.
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Bit
7
6
5
4
3
2
1
0
Whenever any MSR bit 3:0 is set to logic 1, a Modem Status Interrupt will be generated.
Symbol
MSR[7]
MSR[6]
MSR[5]
MSR[4]
MSR[3]
MSR[2]
MSR[1]
MSR[0]
Modem Status Register bits description
Dual UART with 128-byte FIFOs, IrDA, and XScale VLIO bus interface
Description
CD. During normal operation, this bit is the complement of the CD input.
Reading this bit in the loopback mode produces the state of MCR[3]
(OP2A/OP2B).
RI. During normal operation, this bit is the complement of the RI input. Reading
this bit in the loopback mode produces the state of MCR[2] (OP1A/OP1B).
DSR. During normal operation, this bit is the complement of the DSR input.
During the loopback mode, this bit is equivalent to MCR[0] (DTR).
CTS. During normal operation, this bit is the complement of the CTS input.
During the loopback mode, this bit is equivalent to MCR[1] (RTS).
CD
RI
DSR
CTS
logic 0 = no CD change (normal default condition)
logic 1 = the CD input to the SC16C852V has changed state since the last
time it was read. A modem Status Interrupt will be generated.
logic 0 = no RI change (normal default condition)
logic 1 = the RI input to the SC16C852V has changed from a logic 0 to a
logic 1. A modem Status Interrupt will be generated.
logic 0 = no DSR change (normal default condition)
logic 1 = the DSR input to the SC16C852V has changed state since the last
time it was read. A modem Status Interrupt will be generated.
logic 0 = no CTS change (normal default condition)
logic 1 = the CTS input to the SC16C852V has changed state since the last
time it was read. A modem Status Interrupt will be generated.
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Rev. 04 — 14 January 2008
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SC16C852V
© NXP B.V. 2008. All rights reserved.
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