8L4450A 64-Bit Digital I/O with Memory and Counter

You can set a channel to output in either active drive or open collector configurations. When set to ACTive, the module drives the digital lines for both high and low. The voltage level that represents a logic ‘1’ can be set using the SOURce:DIGital:LEVel command. Output voltages can range from 1.66 V (default) to 5 V.

When the channel is set to OCOLlector, lines are driven low, but set to high impedance (Hi- Z) when asserted. In the open collector mode, multiple lines can be connected together by providing external pull- ups.

NOTE

When using external pull-ups in the open collector mode, the outputs will

not exceed 5 V.

 

 

 

Once a channel has been configured, write digital data to the channel using the SOURce:DIGital:DATA command.

SOUR:DIG:DATA:LWOR 26503,(@1201)

You may also use a hexadecimal format to represent values in the commands. For example, to send the decimal value of 26503 in hex use the command form:

SOUR:DIG:DATA:LWOR #h6787,(@1201)

NOTE

Writing to a channel automatically configures the channel as an output.

 

 

 

Note that the data should match the channel width configured using CONFigure:DIGital:DATA:WIDTh command. The data written is masked by the configured width so that any extra bytes will be discarded.

For example: sending the value 65531 to a byte wide channel will result in the channel discarding the upper byte and outputting 251.

Channel Width and Polarity, Threshold, Level, and Drive

When the width of a channel is set to WORD or LWORd, the channel direction (input or output) of the channels spanned by the width is controlled by the channel in operation. That is, all grouped channels are automatically set to the same input or output operation.

Channel settings of polarity, threshold, level, and drive mode are unchanged when channels are combined. For example, consider the following command sequence.

CONF:DIG:POL NORM,(@1101)

CONF:DIG:POL INV,(@1102)

CONF:DIG:WIDT WORD,(@1101)

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L4400 User’s Guide

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Agilent Technologies L4400 manual Channel Width and Polarity, Threshold, Level, and Drive, Not exceed 5