Measurement-computing CIO-DAS16Jr/16 Bedienungsanleitung PDF herunterladen (Seite 15)

3 REGISTER ARCHITECTURE

3.1 CONTROL & DATA REGISTERS

The CIO-DAS16Jr/16 is controlled and monitored by writing to and reading from 16 consecutive 8-bit I/O addresses.

The first address, or BASE ADDRESS, is determined by setting a bank of switches on the board.

Most often, register manipulation is best left to experienced programmers with a specific need for low level control. If

this is the case for you, use the information that follows to write your own code. Otherwise, we strongly suggest you

consider using the Universal Library™ instead.

The register descriptions follow all follow the format:

A/D16

LSB

A/D15A/D14A/D13A/D12A/D11A/D10A/D9

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 hexadecimal, the weights in Table 3-1 apply:

Table 3-1. Bit Weights

801287

40646

20325

10164

883

442

221

110

HEX VALUEDECIMAL VALUEBIT POSITION

To write control or data to a register, the individual bits must be set to 0 or 1 then combined to form a Byte. Data read

from registers must be analyzed to determine which bits are on or off.

The method of programming required to set/read bits from bytes is beyond the scope of this manual. It will be covered in

most Introduction To Programming books, available from a book store.

In summary form, board registers and their function are listed in Table 3-2. Within each register are eight bits which can

constitute a byte of data or can be eight individual bit set/read functions.

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Measurement-computing CIO-DAS16Jr/16 Bedienungsanleitung Seite 15