User`s manual

External Computer
Programming
When the multiplexer is programmed by an external computer through the
E1300/E1301 mainframe or E1406 Command Module, the registers are
accessed using DIAG:PEEK? and DIAG:POKE, or VXI:READ? and
VXI:WRITE.
DIAG:PEEK?/DIAG:POKE and VXI:READ?/VXI:WRITE
Throughput speed using DIAG:PEEK? and DIAG:POKE is faster than
VXI:READ? and VXI:WRITE because the complete register address
(including the A16 starting location 1FC000
16
) is specified. VXI:READ?
and VXI:WRITE specify the device logical address and register offset only.
Thus, the E1300/E1406 processor must calculate the complete register
address which decreases throughput speed.
IBASIC programming using absolute addressing or select code 8 is faster
than either DIAG:PEEK? and DIAG:POKE or VXI:READ? and
VXI:WRITE because the registers are accessed from the VXIbus backplane
rather than from the GPIB. Also, READIO and WRITEIO are not parsed.
Reading the Registers
You can read the following multiplexer registers:
• ID Register (base +00
h
)
• Device Type Register (base +02
h
)
• Status Control Register (base +04
h)
• Tree Switch Registers (base +06
h
)
• Channel Registers (base +08
h)
ID and Device Type
Registers
ID Registers: Reading this register returns: FFFF
h
. This shows Agilent
Technologies as the manufacturer and that the module is an A16 register
based device.
Device Type Register: Reading this register returns:
48-Channel Relay Multiplexer: FF08
h.
Status Control Register Each channel requires about 1 msec to close or open (2 msec for a
close/open cycle). During this time, and also during a reset, the multiplexer
is "busy". The status register returns the following:
"busy": FFF7
h
"not busy": FFFF
h
Tree Switch and
Channel Registers
Always returns FFFF
h
regardless of channel/tree switch state.
Appendix B Agilent E1346A Multiplexer Registers 67