Lead Active Trail
DIN
td(XCOHL-XRDL)
td(XCOH-XA)
td(XCOH-XZCSL)
td(XCOHL-XRDH)
th(XD)XRD
td(XCOHL-XZCSH)
XCLKOUT=XTIMCLK
XCLKOUT= 1/2 XTIMCLK
XZCS0AND1, XZCS2,
XZCS6AND7
XA[0:18]
XRD
XWE
XR/W
XD[0:15]
NOTES: A. All XINTF accesses (lead period) begin on the rising edge of XCLKOUT. When necessary, the device inserts an
alignment cycle before an access to meet this requirement.
B. During alignment cycles, all signals transitions to their inactive state.
C. For USEREADY = 0, the external XREADY input signal is ignored.
D. XA[0:18] holds the last address put on the bus during inactive cycles, including alignment cycles.
tsu(XD)XRD
ta(A)
ta(XRD)
XREADY
SM320F2812-HT
SGUS062A–JUNE 2009 –REVISED APRIL 2010
www.ti.com
6.23 External Interface Read Timing
Table 6-34. External Memory Interface Read Switching Characteristics(1)
PARAMETER MIN MAX UNIT
td(XCOH-XZCSL) Delay time, XCLKOUT high to zone chip-select active low 1 ns
td(XCOHL-XZCSH) Delay time, XCLKOUT high/low to zone chip-select inactive high –2 3 ns
td(XCOH-XA) Delay time, XCLKOUT high to address valid 2 ns
td(XCOHL-XRDL) Delay time, XCLKOUT high/low to XRD active low 1 ns
td(XCOHL-XRDH Delay time, XCLKOUT high/low to XRD inactive high –2 1 ns
th(XA)XZCSH Hold time, address valid after zone chip-select inactive high (2) ns
th(XA)XRD Hold time, address valid after XRD inactive high (2) ns
(1) Not production tested.
(2) During inactive cycles, the XINTF address bus always holds the last address put out on the bus. This includes alignment cycles.
Table 6-35. External Memory Interface Read Timing Requirements(1)
MIN MAX UNIT
ta(A) Access time, read data from address valid (LR + AR) – 14 (2) ns
ta(XRD) Access time, read data valid from XRD active low AR – 12(2) ns
tsu(XD)XRD Setup time, read data valid before XRD strobe inactive high 12 ns
th(XD)XRD Hold time, read data valid after XRD inactive high 0 ns
(1) Not production tested.
(2) LR = Lead period, read access. AR = Active period, read access. See Table 6-25 .

Figure 6-29. Example Read Access

122 Electrical Specifications Copyright © 2009–2010, Texas Instruments Incorporated
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