Table of Contents
Advertisement
3.8
JUMPER SELECTION OF VARIOUS FUNCTIONS
The FDC-3 card has jumper selection for address, interrupts, drive-
ready delay, and Write Fault.
The FDC-3 card leaves the factory with etched jumpers selecting these
functions for proper operation with the TEl, Inc. Disk Operating
System (T/DOS).
Changing any of these jumpers may result in improper
T/DOS operation.
3.8.1
FDC-3 ADDRESS
Recall from SectiCin 3.1 that the basic FDC-3 address is XXOY to XXFY
(hex).
Jumpers insE::rted in the matrix between Z26 and the card edge
connector (Figure 3-3) and the System software determine the specific
FDC-3 address, OY to FY.
The card leaves the factory wtl A7 conn
~cted
to +5 VDC <logic
1>
and
A6-A3 connected to ground (logic 0).
This forms address 8X, where
X
consists of A3 at logic 0 and A2 - AO software-selected from 0-7,
which results in a final address of 80 to 87.
To select a different address,
refer
~o
Table 3-2, determine the
address connection,
c~refully
cut the factory jumpers to Z26 (as
required), then solder jumpers from thE +5VDC or ground rows to the
226 inputs.
3.8.2
END-OF-COMMAND INTERRUPT
with the etched jumper just above 5-100 bus pin
9
intact, the 1791
device generates a VISI interrupt signal
~t
the end of each command.
3.8.3
DATA REQUEST INTERRUPT
With the etched jumper just above pin 10 intact, the 1791 devicE::
generates a VI61 (Data Request) interrupt signal if (1) Data Register
full during Read, or (2) Data Register enpty during vlrite.
3.8.4
WRI'::'E FAUL'I'
If thE:: user's drive supplies a Write-Fault signal (WF/), connecting a
jumper between points
"H"
and "F" below the large signal-cable
connector causes the 1791 device to stop the Write operation and set
the Write-Fault status bit upon
detectio~
of the Fault signal.
3-9
Advertisement
Table of Contents
