Registers | www.ti.com |
4.2Asynchronous 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 | ||||
|
|
| ||||||||||||
15 |
|
|
|
|
| 8 | 7 |
|
|
|
|
|
| 0 |
|
|
|
|
|
|
|
|
|
|
|
|
|
| |
|
|
| Reserved |
|
|
|
| MEWC |
|
|
| |||
|
|
|
|
|
|
|
|
|
|
| ||||
LEGEND: R/W = Read/Write; R = Read only; |
|
|
|
|
|
|
|
|
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. |
|
|
|
|
|
|
|
| Reserved | 0 | Reserved |
| |
|
|
|
|
| |
| CS5_WAIT | 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. |
|
|
|
|
|
| |
| CS4_WAIT | 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. |
|
|
|
|
|
| |
| CS3_WAIT | 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 | |||
|
|
|
|
| Submit Documentation Feedback |
Copyright © 2010, Texas Instruments Incorporated