2192-12132-000-000
An external battery (+VBAT) can be to provide the battery backup for the Real Time Clock and
the SRAM. The external battery will supply power to the battery backup circuit when there is no
+5V supply to the board. The battery voltage must be in the range of 2.8V to 3.3V.
Ethernet Controller
An SMSC LAN91C111 Ethernet controller provides a 10/100-BaseTX interface. The device
provides compliance with IEEE802.3u 100BASE-T specification and IEEE 802.3x Full-duplex
Flow Control. A 93C46 EEPROM is used to store configuration data and MAC information.
An 8-way 0.1” header (PL1) is used to provide signals (see Appendix A for pin assignment
details).
A second 6-way 2mm header (PL2) also provides the user with Activity and Link status LED
signals. The output lines sink current when switched on therefore the anode of each LED should
be connected to PL2’s pins 1,3 or 5 and the cathode to the appropriate status line.
Sound
The AC’97 interface on the PX255 processor along with a National Semiconductor LM4548
AC97 Audio CODEC is used to support Audio on the VIPER. Line In, Line Out and Microphone
interfaces are generated. The Line Out is used to generate an amplified 200mW output, suitable
for driving a 4-8
Ω
load.
Connection is made via a 12-way 0.1” header PL6 (see Appendix A for pin assignments).
Watchdog Timer
The PXA255 contains an internal watchdog timer, which can be used to protect against
erroneous software. Timeout periods can be adjusted from 271
µ
s to 17s. The watchdog timer is
disabled by a RESET. When a timeout occurs, the board will be reset.
Please refer to either an Arcom operating system Technical Manual, or the PXA255 Developers
Manual.
User Configuration Jumpers
There are two user configurable jumpers on the VIPER, LK2 and LK3. The status of these user
jumpers can be read via GP5 and GP7 on the PXA255. If the jumper is inserted then the
corresponding bit will be read as logic ‘0’ (see the “Jumpers and Connectors” section for further
details). These jumpers do not have any defined function on the board; therefore can be used to
select options in your application program.
USB Interface
There are two Universal Serial Bus (USB) interfaces on the VIPER. These interfaces have been
designed to support the Open Host Controller Interface (OpenHCI).
There are four signal lines associated with each USB channel, VBUS, DATA+, DATA- and
GND.
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