SERIES IOS-440 I/O SERVER MODULE 32-CHANNEL ISOLATED DIGITAL INPUT MODULE
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Acromag, Inc. Tel:248-295-0310 Fax:248-624-9234 Email:[email protected] http://www.acromag.com
board unless control of the Interrupt Request Line 0 (IntReq0)
has been enabled via the Interrupt Enable Register (IER).
IOS Identification PROM - (Read Only, 32 Even-Byte
Addresses)
Each IOS module contains an identification (ID) PROM that
resides in the IOS ID space.. This area of memory contains 32
bytes of information at most. Both fixed and variable information
may be present within the ID PROM. Fixed information includes
the "IOS" identifier, model number, and manufacturer's
identification codes. Variable information includes unique
information required for the module. The IOS-440 ID PROM
does not contain any variable (e.g. unique calibration)
information. ID PROM bytes are addressed using only the even
addresses in a 64 byte block. The IOS-440 ID PROM contents
are shown in Table 3.2. Note that the base-address for the IOS
module ID space (see your carrier board instructions) must be
added to the addresses shown to properly access the ID PROM.
Table 3.2: IOS-440 ID Space Identification (ID) PROM
Hex Offset
From ID
PROM Base
Address
Numeric
Value
(Hex)
Field Description
00
49
02
50
04
41
06
43
08
A3
Acromag ID Code
0A
10
IOS Model Code
1
0C
00
Not Used (Rev)
0E
00
Reserved
10
00
Not Used
12
00
Not Used
14
0C
Total Number of
ID PROM Bytes
16
3B
CRC
18 to 3E
00
Not Used
Notes (Table 3.2):
1. The IOS model number is represented by a two-digit code
within the ID PROM (IOS440 model is represented by 10
Hex).
2. Execution of an ID PROM read requires 0 wait states.
THE EFFECT OF RESET
A power-up or bus-initiated software reset will place the
module in the Standard Operating Mode (input only, no event
sensing, no interrupts, and no debounce). Further, all event
inputs are reset, set to positive events, and disabled following
reset. A false input signal is ensured for inputs left floating (i.e.
reads as 0). The Interrupt Enable Register (IER) and Interrupt
Vector Register (IVR) are also cleared (except for IER generated
software resets).
Another form of software reset (IER register initiated) acts
similar to a carrier or power-up reset, except that it is not driven
by the carrier. For the software reset, the Interrupt Vector
Register and Interrupt Enable Register are not cleared. Reset in
this manner has been provided for use when the interrupt vector
and interrupt enable information must be preserved.
Basic Input Operation
Note that the input lines of this module are assembled in
groups of eight. Each group of eight lines is referred to as a port.
Ports 0-3 control and monitor input lines 0-31. Additionally, ports
are grouped eight to a bank. There are four banks of ports used
for controlling this module (Standard Mode, plus Enhanced Mode
Banks 0, 1, and 2), plus 2 additional registers for enabling the
interrupt request line, generating a software reset, and storing the
interrupt vector.
Each port input line is bipolar and accepts both positive and
negative input voltages in two ranges according to the model
number. Individual input lines of a port share a common signal
connection with each other. Separate commons are provided for
each port to facilitate port-to-port isolation. A high signal is
derived from the absolute value of the input voltage measured
between the input line and the port common for the input range of
16-40V for the IOS-440-2 model. Inputs are non-inverting and
inputs left floating (not recommended) will register a low (false=0)
input indication.
In both the Standard and Enhanced operating modes, each
group of eight parallel input lines (a port) are isolated and gated
to the dat
a bus D0..D7 lines. A high input will read as “1” and all
inputs include hysteresis and programmable debounce.
Enhanced Operating Mode
In the Enhanced Mode of operation, each port input may act
as an event sensor and generate interrupts. Likewise,
programmable debounce logic is also available. Event sensing is
used to selectively sense high-to-low level, or low-to-high level
transitions on the input lines at the range thresholds of 6V (“-2”
unit). Event polarities may be defined as positive or negative for
individual nibbles (groups of 4 input lines, or half ports).
Interrupts may also be triggered by events. The optional
debounce logic can act as a filter to “glitches” or transients
present on received signals.
The Enhanced Mode is entered by writing four unique bytes
to the Standard Mode Port 7 register, in consecutive order,
without doing any reads or writes to any other port and with
interrupts disabled. The data pattern to be written is 07H, 0DH,
06H, and 12H, and this must be written immediately after reset or
power-up.
In Enhanced Mode, there are three groups (or banks) of eight
registers or ports. The first group, bank 0, provides register
functionality similar to Standard Mode (input level monitoring).
The second group, bank 1, provides monitor and control of the
event sense inputs. The third group, bank 2, is used to configure
the debounce circuitry for each input while in the Enhanced
Mode.
Event Sensing
The IOS-440 has edge-programmable event sense logic
built-in for all 32 input lines, IN00 through IN31. Event sensing
may be configured to generate an interrupt to the carrier, or to
merely reflect the interrupt internally. Event sensing is enabled in
Enhanced Mode only and inputs can be set to detect positive or
negative events, on a nibble-by-nibble (group of 4 input lines)
basis. The event sensing is enabled on an individual channel
basis. You can combine event sensing with the built-in debounce
