DSPB56364AF100 Datasheet, PDF (43/148 Pages) Freescale Semiconductor, Inc – 24-Bit Audio Digital Signal Processor

External Memory Expansion Port (Port A)
DRAM Type
(tRAC ns)
100
Note: This figure should be use for primary selection. For exact and
detailed timings see the following tables.
80
70
60
50
40 66 80
100 120
Chip Frequency
(MHz)
4 Wait States
11 Wait States
8 Wait States
15 Wait States
AA0475
Figure 3-14 DRAM Out-of-Page Wait States Selection Guide
Table 3-13 DRAM Out-of-Page and Refresh Timings, Four Wait States^{1, 2}
No.
Characteristics³
Symbol
Expression
20 MHz⁴
Min Max
30 MHz⁴
Min Max
Unit
157 Random read or write cycle time
158 RAS assertion to data valid (read)
159 CAS assertion to data valid (read)
160 Column address valid to data valid
(read)
t_RC
t_RAC
t_CAC
t_AA
5 × T_C
250.0
—
166.7
—
ns
2.75 × T_C − 7.5 —
130.0
—
84.2 ns
1.25 × T_C − 7.5 —
55.0
—
34.2 ns
1.5 × T_C − 7.5
—
67.5
—
42.5 ns
161 CAS deassertion to data not valid
t_OFF
(read hold time)
0.0
—
0.0
—
ns
162 RAS deassertion to RAS assertion
163 RAS assertion pulse width
164 CAS assertion to RAS deassertion
t_RP
1.75 × T_C − 4.0 83.5
—
54.3
—
ns
t_RAS
3.25 × T_C − 4.0 158.5
—
104.3
—
ns
t_RSH
1.75 × T_C − 4.0 83.5
—
54.3
—
ns
Freescale Semiconductor
DSP56364 Technical Data, Rev. 4.1
3-27