Hardware UART

Table 17-17. MSR Bit Definitions (Sheet 2 of 2)

Physical Address

Modem Status Register (MSR)

PXA255 Processor Hardware UART

0x4160_0018

 

 

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

7

6

5

4

 

 

 

 

 

 

 

 

 

 

 

 

 

reserved

 

 

 

 

 

 

 

 

 

 

 

 

CTS

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?

?

?

?

?

1

3 2 1

reserved

? ? ?

0

DCTS

0

Bits

Name

 

Description

 

 

 

 

 

CLEAR TO SEND

 

 

Complement of the clear to send (nCTS) input. Equivalent to MCR[RTS] if MCR[LOOP] is

4

CTS

set.

 

 

0

= nCTS pin is 1

 

 

1

= nCTS pin is 0

3:1

reserved

0

DCTS

DELTA CLEAR TO SEND

0

= No change in nCTS pin since last read of MSR

 

 

1

= nCTS pin has changed state

17.5.14Scratchpad Register (SCR)

The SCR, shown in Table 17-18, has no effect on the UART. It is intended as a scratchpad register for use by the programmer. It is included for 16550A compatibility.

This is a read-only register. Ignore reads from reserved bits.

Table 17-18. SCR Bit Definitions

 

 

 

Physical Address

 

 

 

Scratchpad Register (SCR)

 

 

PXA255 Processor Hardware UART

 

 

 

 

 

0x4160_001C

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

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

7

6

5

4

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

SCR

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset

 

 

 

 

 

 

 

 

 

 

 

?

? ? ? ? ? ? ?

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? 0

0

0

0

0

0

0

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bits

 

 

Name

 

 

 

 

 

 

 

 

 

 

 

Description

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

31:8

 

 

 

reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

7:0

 

 

SCR

 

No effect on UART function

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

17.5.15Infrared Selection Register (ISR)

Each UART can manage an IrDA module. The ISR, shown in Table 17-19, controls IrDA functions (see Section 17.4.5).

This is a read/write register. Ignore reads to reserved bits. Write zeros to reserved bits.

17-24

Intel® PXA255 Processor Developer’s Manual

Page 596
Image 596
Intel PXA255 Scratchpad Register SCR, Infrared Selection Register ISR, MSR Bit Definitions Sheet 2, SCR Bit Definitions