Agilent Technologies L4400 - Manual (Page 223)

L4450A 64-Bit Digital I/O with Memory and Counter 8
L4400 User’s Guide 211
Set the number of times to output the trace. Each trace can be output once,
multiple times, or infinitely. The
SOURce:DIGital:MEMory:NCYCles
command sets the number of times to output the trace. If not set to
infinite, you can output the trace from 1 to 255 times (the output is
controlled by the handshake).
Load the trace(s) into memory. Named traces are downloaded using the
TRACe:DATA:DIGital command. The channel width used should match the
width of the channel set in step 1. If you change the width of a bank,

all traces in memory are cleared. The trace names must start with a
character and may be up to 12 characters in length. The trace name used
must be unique to the bank. Up to 32 traces may be downloaded.
Traces can be added or deleted only when memory is disabled. Memory
output cannot be enabled unless the bank has a trace assigned to it.
For example, the following commands load two traces into memory for
bank 1. In this example, each byte of the LWORd to output is sent as a
separate byte.
TRAC:DATA:DIG:LWOR (@1101), MyTrace1, 255, 200, 128, 0

TRAC:DATA:DIG:LWOR (@1101), MyTrace2, 254, 192, 64, 32
You can also send trace data in IEEE- 488 block format using this
command.
The L4450A also has two special built- in traces for your use. You can
generate and download a count- up trace and a walking 1’s pattern using
the
TRACe:DATA:DIGital:FUNCtion command. See the Programmer's
Reference Help file on the L4400 Product Reference CD- ROM for more
details.

You can generate a count-down or walking zero pattern by inverting the
data line polarity.
Set which trace to use. The SOURce:DIGital:MEMory:TRACe command
assigns the desired trace to the bank. This command allows you to switch
between the traces pre- loaded into the bank’s memory.
Enable the memory. Enable the memory on the bank using the
SOURce:DIGital:MEMory:ENABle command. This command sets the
selected trace to be the output and puts the bank in the wait- for- trigger
state.
Trigger the output. When the default trigger source is used, the
SOURce:DIGital:MEMory:STARt command triggers the output. The selected
trace will be output when the handshake occurs.
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