LH79524/LH79525 User’s Guide
External Memory Controller
Version 1.0
7-57
7.5.2.25 Static Memory Page Mode Read Delay Registers (SWAITPAGEx)
The Static Memory Page Mode Read Delay Registers enable programming the delay for
Asynchronous Page Mode sequential accesses.
These registers must only be modified during system initialization, or when there are
no current or outstanding transactions. Software can ensure that there are no current or
outstanding transactions by waiting until the memory controller is idle, then entering
Low-Power Mode (CONTROL:MODE = 1), or Disable Mode (CONTROL:ENABLE = 0).
When in these two modes, external memory access is not allowed, ensuring that
changing parameters will not corrupt external data. Low-Power Mode automatically
refreshes SDRAM; Disable Mode requires commanding the SDRAM to Self Refresh
(DYNMCTRL:SR = 1) prior to entering Disable.
Table 7-60. SWAITPAGEx Register
BIT
31
30
29
28
27
26
25
24
23
22
21
20
19
18
17
16
FIELD
///
RESET
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
TYPE
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
BIT
15
14
13
12
11
10
9
8
7
6
5
4
3
2
1
0
FIELD
///
WAITPAGE
RESET
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
TYPE
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RO
RW
RW
RW
RW
RW
ADDR
0xFF 0x210 for SWAITPAGE0
0xFF 0x230 for SWAITPAGE1
0xFF 0x250 for SWAITPAGE2
0xFF 0x270 for SWAITPAGE3
Table 7-61. SWAITPAGEx Fields
BITS
NAME
FUNCTION
31:5
///
Reserved
Reading returns 0. Write the reset value.
4:0
WAITPAGE
Asynchronous Page Mode Delay
Number of Wait States for Asynchro-
nous Page Mode Read accesses after the first Read:
Asynchronous Page Mode Delay = (WA 1) HCLK cycles