Measurement-computing PC104-DAS08 Manuale Utente Scaricare il pdf (Pagina 14)

READ

On read the most significant A/D byte is read.

The A/D Bits code corresponds to the voltage on the input according to Table 4-3.

Table 3-3. A/D Bit Codes

0 Volts

−Full Scale

½ Full Scale0 Volts8002048

+Full Scale+ Full ScaleFFF4095

UNIPOLARBIPOLARHEXDECIMAL

WRITE

Writing to this register starts a 12-bit A/D conversion.

Note: Place several NO-OP instructions between consecutive 12-bit A/D conversions

to avoid over-running the A/D converter.

3.3 STATUS AND CONTROL REGISTER

BASE ADDRESS + 2

This register address is two registers, one is read active and one is write active.

READ = STATUS

MUX0MUX1MUX2IRQIP1IP2IP3EOC

01234567

EOC = 1 the A/D is busy converting and data should not be read.

EOC = 0 the A/D is not busy and data may be read.

IP3 to IP1 are the digital input lines.

IRQ is the status of an edge triggered latch connected to the “Interrupt Req” pin on

the analog connector. It is high (1) when a positive edge has been detected. It may

be reset to 0 by writing to the INTE mask at BASE + 2 write.

MUX 2 to MUX 0 is the current multiplexer channel. The current channel is a

binary coded number between 0 and 7 .

WRITE = CONTROL

MUX0MUX1MUX2INTEOP1OP2OP3OP4

01234567

OP4 to OP1 are the digital output lines.

1 2 ... 9 10 11 12 13 14 15 16 17 18 19 ... 23 24

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Measurement-computing PC104-DAS08 Manuale Utente Pagina 14