MultiMediaCard Controller

15.5.7MMC_RDTO Register (MMC_RDTO)

MMC_RDTO, shown in Table 15-11, determines the length of time that the controller waits after a command before it turns on the time-out error if data has not been received. The length of time before a time-out occurs is measured in increments of 256 20 MHz periods and can be calculated as follows:

Time-out Delay =

(-----------------------------------------------------------------------------------------MMC_RDTO[READ_TO]) ⋅ (256)

=

(-----------------------------------------------------------------------------------------MMC_RDTO[READ_TO]) ⋅ (128)sec

 

20MHz

 

107

It is the software’s responsibility to calculate the value for READ_TO. The default value is 0xffff, which corresponds to 838.848 ms.

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

Table 15-11. MMC_RDTO Register

 

 

 

Physical Address

 

 

 

 

MMC_RDTO Register

 

 

 

 

MultiMediaCard Controller

 

 

 

 

 

 

0x4110_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

3

2

1

0

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

reserved

 

 

 

 

 

 

 

 

 

 

 

 

READ_TO

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Reset

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

0

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

1

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Bits

 

 

Name

 

 

 

 

 

 

 

 

 

 

 

Description

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

31:16

 

 

 

reserved

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

15:0

 

READ_TO

Specifies the length of time before a data read time-out

 

 

 

 

 

 

 

 

 

15-28

Intel® PXA255 Processor Developer’s Manual

Page 532
Image 532
Intel PXA255 manual Mmcrdto Register Mmcrdto, Readto, Specifies the length of time before a data read time-out