3.The hexadecimal number in bold is the digitizer’s A24 base address.

4.Read the digitizer’s offset register in A16 address space. As shown in Figure C-1, the Offset register is one of the digitizer’s configuration registers.

In a system where the HP E1406 Command Module allocates address space, the A16 base address of the configuration registers is computed as:

1FC00016 + (LADDR * 64)16 2,080,768 + (LADDR * 64)

where 1FC00016 is the starting location of the configuration register addresses, LADDR is the digitizer’s logical address, and 64 is the number of address bytes in A16 per VXI device.

The digitizer’s factory set logical address is 40. If this address is not changed, the base address of the digitizer’s configuration registers in

A16 is:

1FC00016 + (40 * 64)16 1FC00016 + A0016 = 1FCA0016 or decimal

2,080,768 + (40 * 64)

2,080,768 + 2560 = 2,083,328

Given the A16 base address and the "offset" of the Offset register (06 from Figure C-1), the digitizer’s A24 base address can be determined as shown in the program A24_REAL.C.

Appendix C

Register Programming 345

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Image 345
HP E1429A manual Appendix C Register Programming