DS87C550 Datasheet, PDF (39/50 Pages) Dallas Semiconductor – EPROM High-Speed Micro with A/D and PWM

MOVX CHARACTERISTICS CONT’D
Data Hold
after Write
RD Low to
Address Float
t_WHQX
t_RLAZ
0.25t_MCS-5
0.5t_MCS-5
1.5t_MCS-10
RD or WR High
to ALE High
t_WHLH
0
0.25t_MCS-5
1.25t_MCS-10
-((0.125 t_MCS)-5)
10
0.25t_MCS+5
1.25t_MCS+10
DS87C550
C_ST=0
ns
1<=C_ST<=3
4<=C_ST<=7
ns
C_ST=0
ns
1<=C_ST<=3
4<=C_ST<=7
NOTES FOR MOVX CHARACTERISTICS USING STRETCH MEMORY
CYCLES
§ t_MCS is a time period related to the Stretch memory cycle selection. The following table shows the
value of t_MCS for each Stretch selection.
§ C_ST is the stretch cycle value as determined by the MD2, MD1, & MD0 bits of the CKCON register.
t_MCS TIME PERIODS
System Clock Selection
4X/ 2X , CD1, CD0 = 100
4X/ 2X , CD1, CD0 = 000
4X/ 2X , CD1, CD0 = x10
4X/ 2X , CD1, CD0 = x11
t_MCS
0.5 t_CLCL
1 t_CLCL
4 t_CLCL
1024 t_CLCL
RD , WR PULSE WIDTH WITH STRETCH CYCLES
MOVX
RD , WR Pulse Width (in oscillator clocks)
MD2
MD1
MD0
Machine _{4X/ 2X =1 4X/ 2X =0 4X/ 2X =x 4X/ 2X =x}
Cycles _{CD1:0=00 CD1:0=00 CD1:0=10 CD1:0=11}
0
0
0
2
0.5 t_CLCL
1 t_CLCL
2 t_CLCL
2048 t_CLCL
0
0
1
3
t_CLCL
2 t_CLCL
4 t_CLCL
4096 t_CLCL
0
1
0
4
2 t_CLCL
4 t_CLCL
8 t_CLCL
8192 t_CLCL
0
1
1
5
3 t_CLCL
6 t_CLCL
12 t_CLCL
12288 t_CLCL
1
0
0
9
4 t_CLCL
8 t_CLCL
16 t_CLCL
16384 t_CLCL
1
0
1
10
5 t_CLCL
10 t_CLCL
20 t_CLCL
20480 t_CLCL
1
1
0
11
6 t_CLCL
12 t_CLCL
24 t_CLCL
24576 t_CLCL
1
1
1
12
7 t_CLCL
14 t_CLCL
28 t_CLCL
28672 t_CLCL
EXTERNAL CLOCK CHARACTERISTICS
PARAMETER
SYMBOL MIN
Clock High Time
Clock Low Time
Clock Rise Time
Clock Fall Time
t_CHCX
10
t_CLCX
10
t_CLCL
t_CHCL
TYP
MAX
5
5
UNITS
ns
ns
ns
ns
NOTES
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