Measurement-computing PC104-DAC06 Manual de usuario descargar pdf (Pagina 12)

A0A1A2A3A4A5A6A7

01234567

Where the numbers along the top row are the bit positions within the 8-bit byte and

the numbers and symbols in the bottom row are the functions associated with that bit.

To write to or read from a register in decimal or HEX, the bit weights in table 2-1

apply:

Table 2-1. Bit Weights

801287

40646

20325

10164

883

442

221

110

HEX VALUEDECIMAL VALUEBIT POSITION

To write a control word or data to a register, the individual bits must be set to 0 or 1

then combined to form a byte.

The method of programming required to set/read bits from bytes is beyond the scope

of this manual.

In summary form, the registers and their function are listed in Table 2-2. Each

Each DAC has two 8-bit registers which are used to control it. The first register

contains the least-significant eight bits of D/A code. Write to it first.

D12

LSB

D11D10D9D8D7D6D5

01234567

The second register contains the most significant four bits of D/A code. Write to it

last. A write to this register will update the output of the D/A with all 12 bits of the

D/A code contained in the two registers. If the XFER jumper is set for the DAC, no

update will occur until a read of any one of the DAC registers is executed. Upon a

read, all DACs set for simultaneous transfer (XFER jumper set) will update together.

D4D3D2D1

MSB

XXXX

01234567

1 2 ... 7 8 9 10 11 12 13 14 15 16

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Measurement-computing PC104-DAC06 Manual de usuario Pagina 12