ꢀ ꢁꢂ ꢃ ꢄ ꢅ ꢆꢇ ꢈ ꢉꢈ ꢀꢊ ꢀ ꢁꢂ ꢃ ꢄ ꢅ ꢆꢇ ꢈ ꢉꢋ ꢀꢊ ꢀ ꢁꢂ ꢃ ꢄꢅ ꢆꢇ ꢈꢉ ꢇꢀ
ꢌ ꢍꢎ ꢏꢐꢑꢒꢓ ꢍ ꢔꢀ ꢐꢍ ꢕꢍ ꢀꢖꢗ ꢂꢍ ꢕ ꢔꢖꢗ ꢒꢘ ꢓ ꢆꢏ ꢂ ꢂꢓ ꢘ ꢂ
SPRS226H − NOVEMBER 2003 − REVISED AUGUST 2005
PROGRAMMABLE SYNCHRONOUS INTERFACE TIMING (CONTINUED)
READ latency = 2
ECLKOUTx
1
2
1
3
5
CEx
BE1
BE2
BE3
EA3
BE4
ABE[7:0] or BBE[1:0]
4
AEA[22:3] or BEA[20:1]
AED[63:0] or BED[15:0]
EA1
8
EA2
EA4
7
6
Q1
Q2
Q3
Q4
8
9
§
ARE/SDCAS/SADS/SRE
9
§
§
AOE/SDRAS/SOE
AWE/SDWE/SWE
†
These C64x devices have two EMIFs (EMIFA and EMIFB). All EMIFA signals are prefixed by an “A” and all EMIFB signals are prefixed by a
“B”. Throughout the rest of this document, in generic EMIF areas of discussion, the prefix “A” or “B” may be omitted [e.g., the programmable
synchronous interface access signals are shown as generic (SADS/SRE, SOE, and SWE) instead of ASADS/ASRE, ASOE, and ASWE (for
EMIFA) and BSADS/BSRE, BSOE, and BSWE (for EMIFB)].
‡
§
The read latency and the length of CEx assertion are programmable via the SYNCRL and CEEXT fields, respectively, in the EMIFx CE Space
Secondary Control register (CExSEC). In this figure, SYNCRL = 2 and CEEXT = 0.
The following parameters are programmable via the EMIF CE Space Secondary Control register (CExSEC):
−
−
−
Read latency (SYNCRL): 0-, 1-, 2-, or 3-cycle read latency
Write latency (SYNCWL): 0-, 1-, 2-, or 3-cycle write latency
CEx assertion length (CEEXT): For standard SBSRAM or ZBT SRAM interface, CEx goes inactive after the final command has been issued
(CEEXT = 0). For synchronous FIFO interface with glue, CEx is active when SOE is active (CEEXT = 1).
Function of SADS/SRE (RENEN): For standard SBSRAM or ZBT SRAM interface, SADS/SRE acts as SADS with deselect cycles
(RENEN = 0). For FIFO interface, SADS/SRE acts as SRE with NO deselect cycles (RENEN = 1).
Synchronization clock (SNCCLK): Synchronized to ECLKOUT1 or ECLKOUT2
−
−
¶
ARE/SDCAS/SADS/SRE, AOE/SDRAS/SOE, and AWE/SDWE/SWE operate as SADS/SRE, SOE, and SWE, respectively, during
programmable synchronous interface accesses.
Figure 24. Programmable Synchronous Interface Read Timing for EMIFA and EMIFB
†‡§
(With Read Latency = 2)
91
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