UARTs

Table 10-15. MSR Bit Definitions

 

 

 

 

Base+0x18

 

 

 

 

 

Modem Status Register

 

 

 

 

 

 

Bit

31

30

29

28

27

26

25

24

23

22

21

20

19

18

17

16

15

14

13

12

11

10

9

8

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

UART

7 6 5 4 3 2 1 0

DCD RI DSR CTS DDCD TERI DDSR DCTS

0 0 0 0 0 0 0 0

Bits

Name

Description

 

 

 

31:8

reserved

 

 

 

 

 

Data Carrier Detect: Complement of the Data Carrier Detect (nDCD) input. Equivalent to

7

DCD

MCR[OUT2] if MCR[LOOP] is set.

0 – nDCD pin is 1

 

 

 

 

1 – nDCD pin is 0

 

 

 

 

 

Ring Indicator: Complement of the Ring Indicator (nRI) input. Equivalent to MCR[OUT1] if

6

RI

MCR[LOOP] is set.

0 – nRI pin is 1

 

 

 

 

1 – nRI pin is 0

 

 

 

 

 

Data Set Ready: Complement of the Data Set Ready (nDSR) input. Equivalent to

5

DSR

MCR[DTR] if MCR[LOOP] is set.

0 – nDSR pin is 1

 

 

 

 

1 – nDSR pin is 0

 

 

 

 

 

Clear To Send: Complement of the Clear to Send (nCTS) input. Equivalent to MCR[RTS] if

4

CTS

MCR[LOOP] is set.

0 – nCTS pin is 1

 

 

 

 

1 – nCTS pin is 0

 

 

 

3

DDCD

Delta Data Carrier Detect:

0 – No change in nDCD pin since last read of MSR

 

 

1 – nDCD pin has changed state

 

 

 

 

 

Trailing Edge Ring Indicator:

2

TERI

0 – nRI pin has not changed from 0 to 1 since last read of MSR

 

 

1 – nRI pin has changed from 0 to 1

 

 

 

1

DDSR

Delta Data Set Ready:

0 – No change in nDSR pin since last read of MSR

 

 

1 – nDSR pin has changed state

 

 

 

 

 

Delta Clear To Send:

0

DCTS

0 – No change in nCTS pin since last read of MSR

 

 

1 – nCTS pin has changed state

 

 

 

10-20

Intel® PXA255 Processor Developer’s Manual

Page 378
Image 378
Intel PXA255 manual MSR Bit Definitions