DS80C390_00 Datasheet, PDF (19/155 Pages) Dallas Semiconductor – High-Speed Microcontroller User’s Guide Supplement

MD2, MD1, MD0
Bits 2-0
DS80C390 High-Speed Microcontroller User’s Guide Supplement
Stretch MOVX Select 2-0. These bits select the time by which external MOVX
cycles are to be stretched. This allows slower memory or peripherals to be
accessed without using ports or manual software intervention. The RD or WR
strobe will be stretched by the specified interval, which will be transparent to the
software except for the increased time to execute to MOVX instruction. All
internal MOVX instructions are performed at the 2 machine cycle rate.
MD2
0
0
0
0
1
1
1
1
MD1
0
0
1
1
0
0
1
1
MD0
0
1
0
1
0
1
0
1
Stretch Value
0
1
2
3
4
5
6
7
MOVX Duration
2 Machine Cycles
3 Machine Cycles (reset default)
4 Machine Cycles
5 Machine Cycles
9 Machine Cycles
10 Machine Cycles
11 Machine Cycles
12 Machine Cycles
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