Measurement Computing PCM-DAS08 - Manual (Page 13)

Read Status
MA0 MA1 MA2 X DIn0 DIn1 DIn 2
Ex Trig
EOC
0 1 2 3 4 5 6 7
EOC is the end of conversion flag from the A/D converter. A one means the A/D is
busy with a conversion. A zero indicates that the conversion is complete and the data
from the most recently triggered A/D conversion may be read from base + 0 and 1.
DIn 2 / Ex Trig is always one when an external trigger source has been selected via
the TRG bits in Base + 3. Otherwise the status of the TTL input on pin 13 may be
read from this bit. See Base + 3.
Digital Input 0 and 1 are the PCM-DAS08 15 pin connector digital inputs. The
inputs are not latched. Each read gives the current status of the input lines. A zero
equals TTL low and a one equals TTL high.
MA2 to MA0 are the current A/D channel addresses.
BASE + 3 - Trigger Source & Pacer Rate
Write control - No read back. No read function
TRG 0 TRG 1 TRG 2 INT ENA X X X X
0 1 2 3 4 5 6 7
INT ENA: Interrupt Enable. Interrupts are enabled when this bit is set to one and
disabled when set to zero.
Table 5-1. Pacing Source and Rate Coding
TRG 2 TRG 1 TRG 0 A/D Trigger Source and Rate
0 X 0 Software trigger by writing to base address.
0 X 1 External falling-edge trigger on pin 13
1 0 0 Internally triggered and paced at 3.125 kHz
1 0 1 Internally triggered and paced at 6.25 kHz
1 1 0 Internally triggered and paced at 12.5 kHz
1 1 1 Internally triggered and paced at 25 kHz
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