Table 7-29. Doactive Register; Table 7-30. Doactive Fields; Dynamic Memory Last Data Out To Active Time Register (Doactive) - Sharp LH79524 User Manual

LH79524/LH79525 User's Guide
7.5.2.10 Dynamic Memory Last Data Out to Active Time
Register (DOACTIVE)
The Dynamic Memory Last Data Out to Active Time Register enables programming the
Last-data-out to Active Command Time, tAPR. This value is normally found in SDRAM
data sheets as tAPR.
This register 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.
BIT
FIELD
RESET
TYPE
BIT
FIELD
RESET
TYPE
ADDR

Table 7-29. DOACTIVE Register

31 30 29 28 27
0 0 0 0 0
RO RO RO RO RO
15 14 13 12 11
0 0 0 0 0
RO RO RO RO RO

Table 7-30. DOACTIVE Fields

BITS NAME
31:4 /// Reserved Reading returns 0. Write the reset value.
Last-Data-Out to Active Command Time
3:0 tAPR
Time = (tAPR + 1) External Memory Clock periods
26 25 24 23
///
0 0 0 0
RO RO RO RO
10 9 8 7
///
0 0 0 0
RO RO RO RO
0xFFFF1000 + 0x03C
FUNCTION
Version 1.0
External Memory Controller
22 21 20 19 18
0 0 0 0 0
RO RO RO RO RO
6 5 4 3 2
0 0 0 1 1
RO RO RO RW RW
17 16
0 0
RO RO
1 0
tAPR
1 1
RW RW
7-39