Advanced LAN Bypass, User Manual

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9 Advanced LAN Bypass User Manual
Chapter 2
O
VERVIEW
Example 4:

Connects the LAN ports to the host system only when application SW is running
and strobing the WDT

Does not allow any traffic through the unit or bypassing the unit in any other sit-
uation

Sets all segments to the same behavior (master/slave mode is enabled)

A button is required in the front or rear panel that can:
– connect all ports when pushed by the user
– bypass all ports if pushed by the user
2.4 Manual Bypass Control
In addition to the event-driven model, it is also possible to force an action on a spe-
cific LAN bypass segment via the Advanced LAN Bypass SW API. For example, an
application might enable previously disconnected network ports once it starts up and
is ready to process data. The last event will show as "Manual" to distinguish with the
event list in Section 2.3.
2.5 Watchdog Timer
Each segment supports an independent WDT. The timer base is set to 100 ms. The
WDT timeout period can be set between 100 ms and 6553.5 s (approximately 109
min).
Several WDT modes are supported. In addition to the standard WDT mode,
Advanced LAN Bypass also supports an additional feature called "toggle pin mode,"
which reduces the communication latency and overhead between the NIC and LAN
Bypass MCU. It also allows automatic WDT start-up.
Both mechanisms are supported in parallel, meaning that regular WDT control is still
available even though toggle pin mode is enabled.
Meanwhile, both mechanisms are used to strobe the same WDT. WDT expiration will
always trigger a WDT timeout event, regardless of the WDT having been previously
strobed through the toggle pin or a SW API.
2.5.1 Standard Watchdog Mechanism
In this mode, the WDT in the LAN Bypass MCU is controlled by the host SW via the
regular messaging interface. The host SW issues API commands to configure and
start, stop, or reset the WDT (see Section 3.7.4 for more details).
Table 2.4: Mapping between Events and Actions (Example 4)
Event
CONNECT DISCONNECT BYPASS DO_NOT_ CHANGE
Power Up X
Power Down X
Power Reset X
WDT Start X
WDT Timeout X
External Trigger X
Button Event 1 X
Button Event 2 X
Action