Xycom XVME-240 Manual page 33

XVME-240 Manual
October, 1984
Bit 2: Read Only
Bit 1, Bit 0: Read/Write
Status Bits
1 0
0 0
0 1
1 0
The DIO is a non-intelligent module so all diagnos-
tics and configuration checking must be performed
by the system host.
3.3.3 Module I/O Ports Base Address + 88H to 8FH)
The 64 I/O channels used by the DIO module are divided into 8 bidirectional ports with
8 channels to a port. These I/O ports are numbered 0 thru 7. Figure 3-1 shows that
the module I/O ports are addressed consecutively within the module I/O Interface
Block from 88H to 8FH. Table 3-1 lists the I/O Interface Block addresses assigned to
each bidirectional port.
Module I/O Port .
Any I/O port can be accessed by adding the module base address to the particular I/O
Interface Block offset for that port. For
This bit acts as a flag to show if there are any
interrupts pending on the DIO. A logic "1" indicates
that at least one interrupt is pending.
indicates that there are no pending interrupts. This bit
is valid even when interrupts are disabled.
These bits control the red LED and green LED. The red
and green LEDs provide a visual indication of module
status.
A logic "0" turns on the red LED (bit DO).
-
- A logic "1" turns on the green LED (bit D1).
The LEDs will work with user-provided diagnostic soft-
ware to indicate module operational status in the
following manner:
LEDs
Green Red
OFF ON
O F F O F F
ON ON
O N O F F
Table 3-l. Module I/O Port Addresses
.
0
1
2
3
4
5
6
7
SYSFAIL*
O N Module failed, or not yet
tested
O F F Inactive
O N Module undergoing test
O F F Module passed test
NOTE
I/O Interface Block Address
88H
89H
8AH
8BH
8CH
8DH
8EH
8FH
example, I/O port 3 is located at address 8BH
3-6
A logic " 0 "
Status
module