Fluke Biomedical 945A - Manual (Page 51)

MC6802 • MC6808 • MC6802NS
Bus Timing Characteristics
Ident.
Characteristics Symbol MC6802NS MC68A02 MC68B02 UNIT
Number MC6802 MC68A08 MC68B08
MC6808
Min Max Min Max Min Max
1 Cycle Time tcyc 1.0 10 0.667 10 0.5 10 µs
2 Pulse Width, E Low PWEL 450 5000 280 5000 210 5000 ns
3 Pulse Width, E High PWEH 450 9500 280 9700 220 9700 ns
4 Clock Rise and Fall Time tr, tf - - - 25 - - - 25 - - - 20 ns
9 Address Hold Time tAH 20 - - - 20 - - - 20 - - - ns
12 Non-Muxed Address Valid Time tAV1 160 - - - 100 - - - 50 - - - ns
to E (See Note 5) tAV2 - - - 270 - - - - - - - - - - - - ns
17 Read Data Setup Time tDSR 100 - - - 70 - - - 60 - - - ns
18 Read Data Hold Time tDHR 10 - - - 10 - - - 10 - - - ns
19 Write Data Delay Time tDDW - - - 225 - - - 170 - - - 160 ns
21 Write Data Hold Time tDHW 30 - - - 20 - - - 20 - - - ns
29 Usable Access Time tACC 605 - - - 310 - - - 235 - - - ns
(See Note 4)
1
2
3
4 4
10
12
4
9
18
18
29
19
NOTE 4
MPU Read Data Non-Muxed
4
9
18
21
E
Read Data
(Non-Muxed)
R/W, Address
(Non-Muxed)
Write Data
Non-Muxed
17
NOTES:
1.
Voltage levels shown are VL < 0.4 V, VH > 2.4 V, unless otherwise specified.
2. Measurement points shown are 0.8 V and 2.0 V, unless otherwise noted.
3. All electricals shown for the MC6802 apply to the MC6802NS and MC6808, unless otherwise noted.
4. Usable access time is computed by: 12 + 3 + 4 - 17.
5. If programs are not executed from on-board RAM, TAV1 applies. If programs are to be stored and executed from on-
board RAM, TAV2 applies. For normal data storage in the on-board RAM, this extended delay does not apply.
Programs cannot be executed from on-board RAM when using A and B parts ( MC68A02, MC68A08, MC68B02,
MC68B08). On-board RAM can be used for data storage with all parts.
Figure 4-3. Read / Write Timing Diagram
4-27