User`s manual

I/O SERVER User’s Manual Industrial PC
___________________________________________________________________
________________________________________________________________________
Acromag, Inc. Tel:[phone] Fax:[phone] Email:[e-mail] http://www.acromag.com
29
degradation of the I/O Server environmental specifications, Acromag
recommends use of a Solid State (Flash) 2.5” Hard drive. These drives are
available from manufacturers such as Transcend or SanDisk and have no
mechanical parts. Consequently they have superior shock and vibration
and temperature specifications when compared to conventional hard
drives.
There are two types of flash available on the market: multi-level cell
(MLC) and single level cell (SLC). MLC Flash is available in higher
densities and at a lower cost. However, it comes at a cost of read/write
access speed, and low endurance. Endurance for a Flash drive is defined
as the number of write cycles to a bit before the bit may loose its charge
causing a bit error. SLC flash, while in lower densities at a higher cost, is
faster. Additionally it has a far greater endurance (x10) and operates over
the extended temperature range. New technology and assorted
benchmark tests from vendors have blurred the lines of read and write
speed advantages. However, with the greater endurance and larger
temperature range, SLC flash is geared towards the embedded market.
Acromag supplies an 8GB SLC CompactFlash
®
card with the IOS-7400-
WIN model.
The carrier board is a PCI bus slave/target board providing support for
up to four IOS modules. The carrier board’s PCI bus interface allows the
IOS-7400 to control and communicate with IOS modules that are present
on the IOS Carrier. IOS module field I/O connections link through to the
field I/O SCSI2 50 pin connectors. Instructions for removing the IOS
Carrier board and installing IOS modules are provided in Section 2.0 of this
manual.
The PCI bus interface is implemented in the logic of the carrier board’s
PCI bus target interface chip. The PCI bus interface chip implements PCI
specification version 2.2 as an interrupting slave including 8-bit and 16-bit
data transfers to the IOS modules. 32-bit IOS data transfers will be treated
as two 16-bit data transfers.
The carrier board registers are implemented in the logic of the carrier
board’s FPGA. An outline of the functions provided by the carrier board
registers includes:
• Identifying if memory space is enabled in the Carrier Identification
Bits.
• Selecting either an 8MHz or 32MHz clock for each IOS module in the
Clock Control Register.
• Monitoring the error signal received from each IOS module is possible
via the IOS Error Bit.
• Enabling of PCI bus interrupt requests from each IOS module is
possible via the IOS Module Interrupt Enable Bit.
• Enabling of interrupt generation upon an IOS module access time out
is implemented via the Time Out Interrupt Enable Bit.
• Monitoring an IOS module access time out is possible via the IOS
Module Access Time Out Status Bit.
• Identify pending interrupts via the carrier’s IOS Module Interrupt
Pending Bit.
• Lastly, pending interrupts can be individually monitored via the IOS
Module Interrupt Pending Register.
MLC vs. SLC Flash
The 8GB CompactFlash
®
shipped with the
IOS-7400-WIN uses SLC
Flash.
CARRIER BOARD
OVERVIEW
Note that the IOS carrier board
is not hot-swappable
PCI Bus Interface
IOS Carrier Board Re
g
isters