Agilent Technologies L4400 manual Pattern Matching

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

For output operations, the data stored in memory is output as follows:

•BYTE output - first byte in memory on the first handshake, next byte in memory on the second handshake, and so on.

•WORD output - first and second byte in memory on the first handshake, next two bytes in memory on the second handshake, and so on.

•LWORd output - first four bytes in memory on the first handshake, next four bytes in memory on the second handshake, and so on.

Note that for WORD outputs the first byte in memory is considered the most significant byte and is output on the upper bits (15 through 8). For LWORd outputs the first byte is output on bits 31 through 24.

You can change the byte order reported using the FORMat:BORDer command. This command allows you to swap the most- significant and least- significant byte ordering for all data transfer operations. The command is applied globally and cannot be assigned to an individual slot or channel.

Input Operations For input operations (see page page 212), bytes are read into memory as follows:

•BYTE input - the first byte in memory was read on the first handshake, the next byte in memory was read on the second handshake, and so on.

•WORD input - first and second byte in memory were read on the first handshake, next two bytes in memory were read on the second handshake, and so on.

•LWORd input - first four bytes in memory were read on the first handshake, next four bytes in memory were read on the second handshake, and so on.

Note that for WORD inputs the first byte in memory is considered the most significant byte and was read on the upper bits (15 through 8). For LWORd inputs the first byte was read on bits 31 through 24.

Pattern Matching

Pattern matching can be used on input channels only. Pattern matching can be done with or without handshaking. When a pattern match occurs, the L4450A can set an interrupt line or system alarm. A pattern match can also be used to start or stop a buffered (memory) transfer.

Pattern matching is done on a per bank basis and always starts at the first channel of a bank and works up to encompass the configured width of the channel.

Patterns are set up and enabled using the CALCulate subsystem of SCPI commands. For example, the following commands set up a pattern match (#HF00F) and assert the interrupt line when the input pattern is equal to the match pattern.

L4400 User’s Guide 215