116
Bit 12: BE
Description
0
Normal mode: full access
(Initial value)
1
Burst operation: high-speed page mode
•
Bit 11 (CAS Duty (CDTY)): CDTY selects 35% or 50% of the TC state as the high-level duty
ratio of the signal
CAS
in short-pitch access. When cleared to 0, the
CAS
signal high level
duty is 50%; when set to 1, it is 35%.
Bit 11: CDTY
Description
0
CAS
signal high level duty cycle is 50% of the T
C
state (Initial value)
1
CAS
signal high level duty cycle is 35% of the T
C
state
•
Bit 10 (Multiplex Enable Bit (MXE)): MXE determines whether or not DRAM row and
column addresses are multiplexed. When cleared to 0, addresses are not multiplexed; when set
to 1, they are multiplexed.
Bit 10: MXE
Description
0
Multiplexing of row and column addresses disabled
(Initial value)
1
Multiplexing of row and column addresses enabled
•
Bits 9 and 8 (Multiplex Shift Count 1 and 0 (MXC1 and MXC0)): Shift row addresses
downward by a certain number of bits (8–10) when row and column addresses are multiplexed
(MXE = 1). Regardless of the MXE bit setting, these bits also select the range of row addresses
compared in burst operation.
Bit 9:
MXC1
Bit 8:
MXC0
Row Address Shift
(MXE = 1)
Row Address Bits Compared
(in Burst Operation) (MXE = 0 or 1)
0
0
8 bits
(Initial value)
A8–A27
(Initial value)
1
9 bits
A9–A27
1
0
10 bits
A10–A27
1
Reserved
Reserved
•
Bits 7–0 (Reserved): These bits are always read as 0. The write value should always be 0.
Содержание HD6417032
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Страница 525: ...490 CK RAS CAS TRp TRc TRcc tRASD1 tRASD2 tCASD3 tCASD2 TRr tCSR Figure 20 18 Self Refresh ...
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