Finding the Base
Address in an
Embedded Controller
When using an embedded controller such as the HP RADI-EPC7 with the
Standard Instrument Command Library (SICL) for DOS, the A16 base
address is obtained using the
imap
function:
imap(INST id, int mapspace, unsigned int pagestart, unsigned int
pagecnt, char *suggestedaddress);
and using
I_MAP_VXIDEV
as the constant for
mapspace
. The C language
example programs at the end of this appendix use
imap
to get the
E1411B/E1326B base address.
A16 Address Space
Inside the Command
Module or Mainframe
When the A16 address space is inside the command module or mainframe
(Figure C-2), the multimeter’s base address is computed as:
1FC000
16
+ (LADDR * 64)
16
or
2,080,768 + (LADDR * 64)
where 1FC000
16
(2,080,768) is the starting location of the VXI A16
addresses, LADDR is the multimeter’s logical address, and 64 is the
number of address bytes per register-based device. Again, the multimeter’s
factory set logical address is 24. If this address is not changed, the
multimeter will have a base address of:
1FC000
16
+ (24 * 64)
16
= 1FC000
16
+ 600
16
= 1FC600
16
or
2,080,768 + (24 * 64) = 2,080,768 + 1536 = 2,082,304
Figure C-2. Mainframe/Command Module A16 Address Space
Appendix C
HP E1326B/E1411B Multimeter Register-Based Programming 201
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