Status Register - HP E1399A User Manual

Status Register

26 Configuring the HP E1399A
Table 2-3. Data Bus Drivers Parts
Reference HP Part
Designator Number
RP26,32 1810-0279
U16,35 1820-3714
The Status Register is an 8-bit register which provides some specific status
information (as defined by the VXIbus Specification), and which has other
bits available for custom (device dependent) status information as
implemented by the user.
Figure 2-7. Data Bus Drivers
Table 2-4 shows the status register bit definitions. See Chapter 3, "Using the
HP E1399A" for additional information on using the status register. Refer to
the VXIbus Specification, Section C.2.1.1.2, for detailed information
concerning status register implementation restrictions.
Table 2-4. Status Register Bit Definitions
Data Bit(s)
SR0 - SR1
SR2
SR3
SR4 - SR7
As shown in Figure 2-8, the status register circuitry consists primarily of the
data bus line Driver U14, and a resistor network. Table 2-5 shows the parts
list for the status register.
The status register is enabled during a "read status register" operation by the
BASE+4 enable line set low (decoded from address lines A1-A3), and by
Description
Resistor Network, 9- by 4.7kOhm
IC, 74ALS245A-1 Octal Bus Trnscvr, TTL
Definitions
Device Dependent (User assignable)
(0=Failed/Executing Self-test, 1=Passed Self-test)
(If 0, and Passed bit = 1, Extended Self-test active)
Device Dependent (User assignable)
Chapter 2