OMAP-L137
www.ti.com
SPRS563G – SEPTEMBER 2008 – REVISED JUNE 2014
Table 6-23. EMIFA Asynchronous Memory Timing Requirements
(1)
No.
PARAMETER
MIN
NOM
MAX
UNIT
READS and WRITES
E
t
c(CLK)
Cycle time, EMIFA module clock
10
ns
2
t
w(EM_WAIT)
Pulse duration, EM_WAIT assertion and deassertion
2E
ns
READS
12
t
su(EMDV-EMOEH)
Setup time, EM_D[15:0] valid before EM_OE high
3
ns
13
t
h(EMOEH-EMDIV)
Hold time, EM_D[15:0] valid after EM_OE high
0
ns
14
t
su (EMOEL-EMWAIT)
Setup Time, EM_WAIT asserted before end of Strobe Phase
(2)
4E+3
ns
WRITES
28
t
su (EMWEL-EMWAIT)
Setup Time, EM_WAIT asserted before end of Strobe Phase
(2)
4E+3
ns
(1)
E = EMA_CLK period or in ns. EMA_CLK is selected either as SYSCLK3 or the PLL output clock divided by 4.5. As an example, when
SYSCLK3 is selected and set to 100MHz, E=10ns.
(2)
Setup before end of STROBE phase (if no extended wait states are inserted) by which EM_WAIT must be asserted to add extended
wait states.
Figure 6-18
and
Figure 6-19
describe EMIF transactions that include extended wait states inserted during the STROBE
phase. However, cycles inserted as part of this extended wait period should not be counted; the 4E requirement is to the start of where
the HOLD phase would begin if there were no extended wait cycles.
Table 6-24. EMIFA Asynchronous Memory Switching Characteristics
(1) (2) (3)
No.
PARAMETER
MIN
NOM
MAX
UNIT
READS and WRITES
1
t
d(TURNAROUND)
Turn around time
(TA)*E - 3
(TA)*E
(TA)*E + 3
ns
READS
(RS+RST+RH)*E
(RS+RST+RH)*E
EMIF read cycle time (EW = 0)
(RS+RST+RH)*E
ns
- 3
+ 3
3
t
c(EMRCYCLE)
(RS+RST+RH+E (RS+RST+RH+EWC
(RS+RST+RH+E
EMIF read cycle time (EW = 1)
ns
WC)*E - 3
)*E
WC)*E + 3
Output setup time, EMA_CE[5:2] low to
(RS)*E-3
(RS)*E
(RS)*E+3
ns
EMA_OE low (SS = 0)
4
t
su(EMCEL-EMOEL)
Output setup time, EMA_CE[5:2] low to
-3
0
+3
ns
EMA_OE low (SS = 1)
Output hold time, EMA_OE high to
(RH)*E - 3
(RH)*E
(RH)*E + 3
ns
EMA_CE[5:2] high (SS = 0)
5
t
h(EMOEH-EMCEH)
Output hold time, EMA_OE high to
-3
0
+3
ns
EMA_CE[5:2] high (SS = 1)
Output setup time, EMA_BA[1:0] valid to
6
t
su(EMBAV-EMOEL)
(RS)*E-3
(RS)*E
(RS)*E+3
ns
EMA_OE low
Output hold time, EMA_OE high to
7
t
h(EMOEH-EMBAIV)
(RH)*E-3
(RH)*E
(RH)*E+3
ns
EMA_BA[1:0] invalid
Output setup time, EMA_A[13:0] valid to
8
t
su(EMBAV-EMOEL)
(RS)*E-3
(RS)*E
(RS)*E+3
ns
EMA_OE low
Output hold time, EMA_OE high to
9
t
h(EMOEH-EMAIV)
(RH)*E-3
(RH)*E
(RH)*E+3
ns
EMA_A[13:0] invalid
EMA_OE active low width (EW = 0)
(RST)*E-3
(RST)*E
(RST)*E+3
ns
10
t
w(EMOEL)
EMA_OE active low width (EW = 1)
(RST+EWC)*E-3
(RST+EWC)*E
(RST+EWC)*E+3
ns
t
d(EMWAITH-
Delay time from EMA_WAIT deasserted to
11
3E-3
4E
4E+3
ns
EMOEH)
EMA_OE high
WRITES
(1)
TA = Turn around, RS = Read setup, RST = Read strobe, RH = Read hold, WS = Write setup, WST = Write strobe, WH = Write hold,
MEWC = Maximum external wait cycles. These parameters are programmed via the Asynchronous Bank and Asynchronous Wait Cycle
Configuration Registers. These support the following range of values: TA[4-1], RS[16-1], RST[64-1], RH[8-1], WS[16-1], WST[64-1],
WH[8-1], and MEW[1-256].
(2)
E = EMA_CLK period or in ns. EMA_CLK is selected either as SYSCLK3 or the PLL output clock divided by 4.5. As an example, when
SYSCLK3 is selected and set to 100MHz, E=10ns.
(3)
EWC = external wait cycles determined by EMA_WAIT input signal. EWC supports the following range of values EWC[256-1]. Note that
the maximum wait time before timeout is specified by bit field MEWC in the Asynchronous Wait Cycle Configuration Register.
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