Racal Instruments 1260 VXI, User Manual

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1260-145 User Manual
Module Operation 3-6 Racal Instruments

2003
Operating The
1260-145 in
Register-Based
Mode
In register-based mode, the 1260-145 is operated by directly
writing and reading to/from ports controlling eight relays each. To
access the various registers the following details must be
assembled to generate an absolute address that can be wrote or
read from:
The control registers are located in the VXIbus A24 Address
Space. The A24 address for a control register depends on:
1. The A24 Address Offset assigned to the 1260-01T module by
the Resource Manager program. The Resource Manager
program is provided by the VXIbus slot-0 controller vendor.
The A24 Address Offset is placed into the “Offset Register” of
the 1260-01T by the Resource Manager.
2. The <module address> of the 1260-145 module. This is a
value in the range from 1 and 12 inclusive.
3. The 1260-145 control register to be written to or read from.
Each register on the 1260-145 has a unique offset from the
base address.
The base A24 address for the 1260-145 module may be calculated
by:
(A24 Offset of the 1260-01T) + (1024 x Module Address of
1260-145).
The A24 address offset is usually expressed in hexadecimal. A
typical value of 204000
16
is used in the examples that follow.
A 1260-145 with a module address of 7 would have the base A24
address computed as follows:
Base A24 Address of 1260-145 = 204000
16
+ (400
16
x 7
10
)
= 205C00
16
The control registers for Adapt-a-Switch plug-ins and conventional
1260-Series modules are always on odd-numbered A24
addresses. This number can be obtained for a given card and a
given relay by referring to
Figure 3-3 and one of the applicable
card types illustrated in Figures 3-5 through 3-11 . These figures
provide a register-based address offset and bit position ( Off-bit )
for each unique relay on any 1260-145 card. Once this offset is
known, the absolute address where data is to be written or read
from is simply assembled by adding the base address to the offset:
(Base A24 1260-145 Address) + offset = absolute address
If slot 7 is assumed to be occupied by a 1260-145A card for