Table of Contents
Advertisement
Embedded Computer
Programming
(C-Size Systems)
IBASIC Programming
The Register Offset
and Register Number
66
HP E1346A Multiplexer Registers
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
If the E1346A multiplexer is part of a C-Size VXI system, the fastest
throughput is achieved using an embedded computer. The embedded
computer allows you to access the registers from the VXIbus backplane,
and thus, there is no parsing of SCPI command headers.
When the E1346A multiplexer is programmed using the E1300/E1301
Mainframe's Instrument BASIC (IBASIC), two methods of accessing the
registers are through absolute addressing or using select code 8.
Absolute Addressing and Select Code 8
Absolute addressing is faster than select code 8 since the complete register
address (including the A16 starting location 1FC000
select code 8 is used, the IBASIC processor must calculate the complete
register address based on the logical address specified (Table B-1).
Depending on whether absolute addressing or select code 8 is used, either a
register offset or register number is specified as part of the register address.
Absolute addressing specifies a register offset, which is the register's
location in the block of 64 address bytes. For example, the multiplexer's
Channel Register has an offset of 08
register, the offset is added to the base address to form the register address
(using a logical address of 80):
register address =base address +register offset
= 1FC000
= 1FC000
or
= 2,080,768 + (80 * 64) + 8
= 2,080,768 + 5120 + 8 = 2,085,896
Using select code 8 requires that you specify a register number. The
register number is the register offset/2. Referring to Figure B-1, the
Channel register with an offset of 08, is register number 4.
. When you write a command to this
16
+ (80 * 64)
+ 08
16
16
16
+ 1400
+ 08
= 1FD408
16
16
16
) is specified. When
16
16
Appendix B
Advertisement
Table of Contents
