Agilent Technologies L4400 User Manual
Page 221
L4450A 64-Bit Digital I/O with Memory and Counter
8
L4400 User’s Guide
209
Optionally, you can provide an external strobe input on the H2 line to
control the memory transfers. If you pace the memory inputs from an
external clock, the L4450A will sense the leading edge of the strobe and
set the data. The data will be valid after T
PD
and the receiving device may
latch the data. T
PD
ranges from 140 ns to 60 ns. The maximum T
PD
of 140
ns limits operation in this mode to 7 MHz.
A synchronous buffered output using an external clock is shown in the
diagram below (default handshake line polarity).
H0 (Start/Stop)
H2 (Clock In)
Data Out
Valid
T
CYC LE
(Last Cycle)
Invalid
T
PD
T
PD
T
PD
For example, using the internal strobe, the following SCPI commands set
the L4450A to have a 32- bit output using synchronous handshake. The
number of times to output the traces is set to 4. A trace is then loaded
into memory and assigned to the channel. The memory is enabled and
then triggered. The start/stop line is set high following the first byte
handshake and remains high until the last byte is output.
CONF:DIG:WIDT LWOR, (@1101)
CONF:DIG:DIR OUTP, (@1101)
CONF:DIG:HAND SYNC, (@1101)
SOUR:DIG:MEM:NCYC 4, (@1101)
TRAC:DATA:DIG:LWOR (@1101), mytrace, #hFFEEFFEE, #hBCBC9999
SOUR:DIG:MEM:TRAC mytrace,(@1101)
SOUR:DIG:MEM:ENAB ON, (@1101)
SOUR:DIG:MEM:STAR (@1101)
Using an external strobe, the following SCPI commands set the L4450A to
have an 8- bit output using synchronous handshake with an external strobe
input. The number of times to output the traces is set to infinite
(continuous output until the memory is stopped). The memory is enabled
and then triggered. The start/stop line is set high following the first byte
handshake and remains high until the last byte is output.
CONF:DIG:WIDT BYTE, (@1101)
CONF:DIG:DIR OUTP, (@1101)
CONF:DIG:HAND SYNC, (@1101)
CONF:DIG:HAND:SYNC:STR:SOUR EXT, (@1101)
SOUR:DIG:MEM:NCYC 0, (@1101)
TRAC:DATA:DIG:BYTE (@1101), mytrace, 260, 139
SOUR:DIG:MEM:TRAC mytrace,(@1101)
SOUR:DIG:MEM:ENAB ON, (@1101)
SOUR:DIG:MEM:STAR (@1101)