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Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
August 2006
Developer’s Manual
Order Number: 306262-004US
605
Memory Controller—Intel
®
IXP45X and Intel
®
IXP46X Product Line of Network Processors
Figure 112. MCU DDR Write Command to Next Command Timing Diagrams
Notes:
1.
Nominal t
DQSS
assumed
2.
t
WTR
= first pos. clock after last Data
3.
Burst Writes cannot interrupt previous Writes
B4219-001
t0
t1
t2
t3
t4
t5
t6
t7
t8
t9
t10
m_clk
CMD
non-reg,
BL=4, CAS=X
0 1
0 1 2 3
non-reg,
BL=4, CAS=4
t
WL
=1
t
WR
=2
t
WL
=3
t
WR
=2
Next allowed Non-Read Command: reg, BL=4.
Next allowed Read: reg, BL=4.
t
WTR
=1
t
WTR
=1
t
WTCMD
=tWL + (BL/2) +t
WR
+ t
REG
t
WTRD
=t
WL
+ (BL/2) +t
WTR
+ t
REG
Write Duration Equations:
EX
A
EX
B
t
WTRD
t
WTCMD
Example A: non-reg, BL=4.
t
WRCMD
=(1+(4/2)+2+0)=5
t
WTRD
=(1+(4/2)+1+0)=4
W
Example B: reg, BL=4, t
WL
=3
t
WTCMD
=(3+(4/2)+2+0)=7
t
WTRD
=(3+(4/2)+1+0)=6
Programming Examples:
CMD
W
2 3
non-reg DIMMs)
(possible
ONLY
for