Measurement Computing CIO-DAS6402/12 - Manual (Page 24)

COMPATIBLE MODE:
Write to Base + 8 only clears the interrupt flip-flop (sets CLRINT only (= 1)).
5.7 INTERRUPT AND PACER CONTROL REGISTER
BASE ADDRESS +9 Example, 309h, 777 Decimal
READ/WRITE
HC_PS0 HC_PS1 DMAEN XINTE HC_IS0 HC_IS1 HC_IS2 INTE COM
HC_PS0 HC_PS1 BURSTE XINTE HC_IS0 HC_IS1 HC_IS2 INTE ENH
0 1 2 3 4 5 6 7
INTE =1, Analog Interrupts are enabled, =0, interrupts are disabled.
The system interrupt level is determined by the three HC_IS0-2 bits. The interrupt source (Single AD, FIFO Half-Full, End of
Burst) is selected by the two Analog Interrupt Source bits HC_AI0 & HC_AI1 (Base + 11). Use of external interrupt (XINTE) also
requires that INTE = 1.
HC_IS2, HC_IS1, HC_IS0 will map an enabled interrupt onto a specific ISA bus interrupt level. See Table 6-4 below:
Table 5-4. Interrupt Levels - Enhanced & Compatible
7 7 1 1 1
6 15 0 1 1
5 5 1 0 1
none - see Note 10 0 0 1
3 3 1 1 0
2 2 0 1 0
none 11 1 0 0
none none 0 0 0
Compatible (ref) Interrupt Level- Enhanced HC_IS0 HC_IS1 HC_IS2
Note: Some Interrupt levels in Enhanced Mode are different from Interrupt levels in Compatible Mode. IRQ4 was dropped from
the Compatible-mode IRQ's to allow a single GAL to decode all IRQ's, and since COM1 uses IRQ4, the DAS1600 will probably
never use it.
XINTE: =1, External Interrupt enabled. =0, External Interrupt disabled. The external interrupt is a direct digital path from the
100-pin connector to the system interrupt. External Interrupt shares the Interrupt Level with the Analog Interrupt path. (Only
enabled in Enhanced mode).
BURSTE When = 1, Burst Mode is enabled. When = 0, Burst Mode is disabled. The number of channels in the burst is
determined by the Mux Hi/Lo register.
(BURST Mode also enabled by write to BASE + 406hex bit 6 as on DAS1600 series).
HC_PS1, HC_PS0: Controls the source of the A/D conversion Pacer according Table 6-5 below:
Table 5-5. Control Source of A/D Conversion Pacer
Internal Pacer (8254) 1 1
External Pacer Rising Edge 0 1
External Pacer Falling Edge 1 0
Software Convert 0 0
Pacer Source HC_PS0 HC_PS1
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