![background image](http://html1.mh-extra.com/html/omega/isa-bus-multi-functional-board-ome-a822pg/isa-bus-multi-functional-board-ome-a822pg_hardware-manual_3926786019.webp)
2.4.1 8254 Counter
The 8254 Programmable timer/counter has 4 registers from Base+0 through
Base+3. For detailed programming information on the 8254 , please refer to
Intel‘s “Microsystem Components Handbook”.
Address
Read
Write
Base+0
8254 Counter 0
8254 Counter 0
Base+1
8254 Counter 1
8254 Counter 1
Base+2
8254 Counter 2
8254 Counter 2
Base+3
Reserved
8254 Counter Control
2.4.2 A/D Input Buffer Register
(READ) Base+4 : A/D Low Byte Data Format
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
D7 D6 D5 D4 D3 D2 D1 D0
(READ) Base+5 : A/D High Byte Data Format
Bit 7
Bit 6
Bit 5
Bit 4
Bit 3
Bit 2
Bit 1
Bit 0
0 0 0 READY
D11
D10
D9
D8
A/D 12 bit data : D11…..D0, D11=MSB, D0=LSB
READY =1 : A/D 12 bit data not ready
=0 : A/D 12 bit data is ready
The low 8 bit A/D data is stored in address BASE+4 and the high 4 bit data is stored in
address BASE+5. The READY bit is used as an indicator for the A/D conversion.
When an
A/D conversion is completed, the READY bit will clear to zero.
OME-A-822PGL/PGH Hardware Manual ----
17
Содержание ISA- BUS MULTI-FUNCTIONAL BOARD OME-A822PG
Страница 3: ...OME A 822PGH PGL Enhanced Multi Function Card Hardware Manual OME A 822PGL PGH Hardware Manual 1...
Страница 36: ...Figure 2 Figure 3 OME A 822PGL PGH Hardware Manual 34...
Страница 50: ...DMA no and IRQ no selection screen OME A 822PGL PGH Hardware Manual 48...
Страница 61: ...5 2 5 Help The Help menu will display the software version as shown below OME A 822PGL PGH Hardware Manual 59...