BusWorks
®
900EN-S005 Ethernet Switch User’s Manual Ethernet I/O
___________________________________________________________________
_______________________________________________________________________________________
Acromag, Inc. Tel:248-624-1541 Fax:248-624-9234 Email:
http://www.acromag.com
59
Frame Buffer:
64K Bytes (16Kx32 Bits) of SRAM shared across all 5 ports
for frame storage (providing 512 buffers of 128 Bytes each). Resource
is shared among 5 ports, or optionally, allocated one-fifth per port. A
single frame can vary from 64 Bytes up to 1536 Bytes. This is effective
storage for as little as 42 messages, or as much as 1024 messages.
Communication Distance:
The distance between two devices on an
Ethernet network is generally limited to 100 meters using recommended
copper cable. Distances may be extended using hubs, switches, or
fiber optic transmission. However, the total round trip delay time must
not exceed 512 bit times for collision detection to work properly.
Broadcast Storm Protection:
Disabled (default), but may optionally select
a maximum receive threshold for multicast/broadcast messages.
Broadcast packets are discarded if they exceed the configured
threshold within a preset amount of time (refer to Advanced Operation
for more detailed information).
Priority:
Transmit all high priority before any low priority (default) with a
variable high:low interleave (optional). Optionally select DiffServ,
802.1p, and port-based priority controls (refer to Advanced Operation
for more detailed information).
Virtual LAN:
Supports port-based Virtual LAN definitions using EEPROM
Mode (refer to Advanced Operation for more detailed information).
This is the default mode of operation. A bank of 8 DIP switches (S1) and 4
DIP switches (S2) allows some operating parameters of this device to be
modified and optional modes of operation selected. These switches are
located in the top opening adjacent to the power terminals and reset button.
DIP switch S2-1 must be OFF to enable use of DIP switches S2-4 and S1-
1..8. In this mode, DIP switch settings are combined with the defaults noted
for the operating parameters not directly covered by a DIP switch (see
Register Map). Refer to Basic Operation for more information on using the
DIP switches to configure operation.
This I
2
C interface provides direct read/write access to switch configuration
registers in EEPROM memory on board for more extensive control of
available features and options than the DIP switches alone. Access to this
interface is provided via socket P1, which is nested in the opening with the
DIP switches. Use this interface to set up the switch prior to installation. An
optional program cable is required to connect this module to the host PC
parallel port (Acromag cable Model 5035-365). Refer to the EEPROM Mode
section of this manual for more information on available features.
Connector (P1):
This buffered combination I
2
C/SPI interface uses the
same connector and cable as for SPI access (Acromag Cable Model
5035-365). DIP switch S2-3 must be OFF and switch S2-2 ON to
provide EEPROM access. DIP switch S2-1 must be ON to cause the
module to use the EEPROM settings (as opposed to the other DIP
switches) upon power-up or after a reset.
EEPROM:
Atmel AT24C02 or equivalent, 2K (256x8bits) serial EEPROM.
Refer to EEPROM Mode of Advanced Operation for information on
programming.
Signals (P1 Program Interface):
Socket P1 combines I
2
C, SPI, and
ground signals for EEPROM programming, or optional run-time
operation in SPI Slave Mode. The following signals are supported:
Ethernet Interface
Broadcast storm protection,
priority selection, and Virtual
LAN definitions require
configuration software and an
optional cable (Model 5035-
365) in order to program.
Program Interface –
DIP Switches
Program Interface –
EEPROM/I
2
C
