Racal Instruments 7064 Instruction Manual page 60

5.2.1.3 I D Register
5.2.1.3.1 The breadboard implements all bits of the ID register. The bits are controlled by
S2 and S3. The switches and the bits they control are shown in the section of the
manual on switch settings. These bits are used to identify the manufacturer, the
address space and the device class. Manufacturer ID numbers are obtained from
the VXlbus consortium. Address space indicates the addressing modes o f the
device's operational registers (e.g., A 16 only is indicated by both bits set high).
Device class refers to the type o f instrument this is (e.g., register-based is
indicated by both bits set high). Refer to the section in the manual on switch
settings and the VXlbus standard for detailed information.
5.2.1.4 D e v i c e Type Register
5.2.1.4.1 T h e breadboard implements all bits o f the Device Type register. The bits are
controller by S4 and S5. The switches and the bits they control are shown in the
section o f the manual on switch settings. These bits are used to identify the
instrument model and tell how much memory space is required by this instrument.
The manufacturer is at liberty to set the model to almost any code desired.
Model codes 0 to 255 are reserved for slot 0 devices, and in most cases,
should not be used.
5.2.1.4.2
Required memory is indicated by the upper four bits of the device type register.
If the instrument is an A16 only device, the upper four bits are used as an
extension of the model number. Refer to the schematic and the VXlbus standard
for detailed information .
5.2.1.5 A d d i t i o n a l Read Registers - Internal Decoding
5.2.1.5.1 D e c o d i n g is provided for some additional read registers. Because each decoded
control signal is for 16 bits and the internal bus is 32 bits wide, the user must pay
attention to which group o f 16 data bits to connect to any added registers.
Controls RBASE+8 and RBASE+C should be used with BDO through BD15.
Controls RBASE+6, RBASE+A and RBASE+E should be used with BD16
through BD31. Controller accesses of 16 and 32 bits are automatically handled.
The decoded control signals appear at P11, the user interface connector. Here is
an example of how some additional registers can be added:
NOTE
5-3