Table of Contents
Advertisement
Register Addressing in the VXIbus Environment
Logical address
Each module in a VXIbus system, whether VXI or M-Module, must have a
unique logical address. The HP E2251 Carrier provides a logical address for
each installed M-Module. Refer to the HP E2251 Carrier Installation and
Wiring Manual and the HP E2251 User's Manual for details. If you are
using a different carrier, refer to that carrier's documentation for
register-based addressing information.
A16/A24 Memory
The VXI Specification allows for only 64 bytes of address space in A16
memory. However, the M-Module specification defines 256 bytes of
Mapping
address space. To resolve this conflict, the HP E2251 Carrier provides two
memory segments for each installed M-Module. The first is in A16 memory
space and contains the standard VXI registers. The second memory segment
is in the A24 memory space and contains all other M-Module registers (these
registers are described later in this chapter). Figure 4-4 shows the A16/A24
memory mapping for a typical M-Module.
Note
The M-Module's ID word (from the ID EEPROM) is mapped into the VXI
Manufacturer ID register at address 00
(A16 memory) and the
h
M-Module's VXI device Type word is mapped into the VXI Device Type
Register at address 02
(A16 memory).
h
Figure 4-4. Typical M-Module A16/A24 Memory Mapping in an HP E2251 Carrier
Register Programming Information
59
Advertisement
Table of Contents
