Section 4.2 – Texas Instruments TMS320DM646X DMSOC User Manual

Page 50

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Registers

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4.2

Asynchronous Wait Cycle Configuration Register (AWCCR)

The asynchronous wait cycle configuration register (AWCCR) is used to configure the parameters for
extended wait cycles. Both the polarity of the EM_WAIT[5:2] pins and the maximum allowable number of
extended wait cycles can be configured. the AWCCR is shown in

Figure 21

and described in

Table 34

.

NOTE:

The EW bit in the asynchronous configuration register (ACFGn) must be set to allow for the

insertion of extended wait cycles.

Figure 21. Asynchronous Wait Cycle Configuration Register (AWCCR)

31

30

29

28

27

24

23

22

21

20

19

18

17

16

WP3

WP2

WP1

WP0

Reserved

CS5_WAIT

CS4_WAIT

CS3_WAIT

CS2_WAIT

R/W-1

R/W-1

R/W-1

R/W-1

R-0

R/W-3h

R/W-2h

R/W-1

R/W-0

15

8

7

0

Reserved

MEWC

R-0

R/W-80h

LEGEND: R/W = Read/Write; R = Read only; -n = value after reset

Table 34. Asynchronous Wait Cycle Configuration Register (AWCCR) Field Descriptions

Bit

Field

Value

Description

31

WP3

WAIT polarity bit. This bit defines the polarity of the EM_WAIT[5] pin.

0

Insert wait cycles if EM_WAIT[5] pin is low.

1

Insert wait cycles if EM_WAIT[5] pin is high.

30

WP2

WAIT polarity bit. This bit defines the polarity of the EM_WAIT[4] pin.

0

Insert wait cycles if EM_WAIT[4] pin is low.

1

Insert wait cycles if EM_WAIT[4] pin is high.

29

WP1

WAIT polarity bit. This bit defines the polarity of the EM_WAIT[3] pin.

0

Insert wait cycles if EM_WAIT[3] pin is low.

1

Insert wait cycles if EM_WAIT[3] pin is high.

28

WP0

WAIT polarity bit. This bit defines the polarity of the EM_WAIT[2] pin.

0

Insert wait cycles if EM_WAIT[2] pin is low.

1

Insert wait cycles if EM_WAIT[2] pin is high.

27-24

Reserved

0

Reserved

23-22

CS5_WAIT

0-3h

EM_WAIT[5:2] pin map for chip select 5. By default, the EM_WAIT[5] pin is used for chip select 5.

0

EM_WAIT[2] pin is used.

1h

EM_WAIT[3] pin is used.

2h

EM_WAIT[4] pin is used.

3h

EM_WAIT[5] pin is used.

21-20

CS4_WAIT

0-3h

EM_WAIT[5:2] pin map for chip select 4. By default, the EM_WAIT[4] pin is used for chip select 4.

0

EM_WAIT[2] pin is used.

1h

EM_WAIT[3] pin is used.

2h

EM_WAIT[4] pin is used.

3h

EM_WAIT[5] pin is used.

19-18

CS3_WAIT

0-3h

EM_WAIT[5:2] pin map for chip select 3. By default, the EM_WAIT[3] pin is used for chip select 3.

0

EM_WAIT[2] pin is used.

1h

EM_WAIT[3] pin is used.

2h

EM_WAIT[4] pin is used.

3h

EM_WAIT[5] pin is used.

50

Asynchronous External Memory Interface (EMIF)

SPRUEQ7C – February 2010

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