GXLV Datasheet, PDF (202/247 Pages) National Semiconductor (TI) – Geode™ GXLV Processor Series Low Power Integrated x86 Solutions

Electrical Specifications (Continued)
Table 6-17. SDRAM Interface Signals (Refer to Figures 6-9 and 6-10)
Symbol Parameter
Min
Max
Unit
t1
RASA#, RASB#, CASA#, CASB#,
t1 Min = z – 1.5
WEA#, WEB#, CKEA, CKEB,
DQM[7:0], CS[3:0]# Ouput Valid from
SDCLK[3:0]
t1 Max = z – 1.0
ns
t2
MA[12:0], BA[1:0] Output Valid from
SDCLK[3:0]
t2 Min = z – 1.7
t2 Max = z – 1.2
ns
t3
MD[63:0] Output Valid from
SDCLK[3:0]
t2 Min = z – 1.6
t3 Max = z – 0.3
ns
t4
MD[63:0] Read Data in Setup to
0
ns
SDCLK_IN
t5
MD[63:0] Read Data Hold to
2.0
ns
SDCLK_IN
Calculation of minimum and maximum values of t1, t2, and t3: (see Figure 4-10 on page 124)
x =shift value applied to SHFTSDCLK field where SHFTSDCLK field = GX_BASE+8404h[5:3].
y = core clock period ÷ 2
z = (x * y)
Equation Example:
A 200 MHz GXLV processor interfacing with a 66 MHz SDRAM bus, having a shift value of 2:
x=2
core clock period = 1/(200 MHz) = 5 ns
y=5÷2
t1 Min = (2 * (5 ÷ 2)) – 1.5 = 3.5 ns
t1 Max = (2 * (5 ÷ 2)) – 1.0 = 4.0 ns
SDCLK[3:0]
CNTRL, MA[12:0],
BA[1:0], MD[63:0]
t1, t2, t3
Valid
Figure 6-9. Output Valid Timing
SDCLK_IN
MD[63:0]
Read Data In
t5
t4
Data Valid
Data Valid
Figure 6-10. Setup and Hold Timings - Read Data In
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