User's Manual

XFIN-BLADE-SM
TECHNICAL DESCRIPTION PAGE 31
4.2.2.4 Power
The control board requires a 12V 2000ma supply. Linear regulators are provided to reduce
the input voltage down to 10V and 5V for the audio circuits. The input voltage supply is
also regulated down to 3.3V for the digital logic via a switched mode power supply. The
1.3V supply for the IXP processor core is generated by a regulator off the 3.3V rail. The
1.2V supply for the DSP core is generated by a diode (controlled by the DSP) off the 3.3V
rail.
4.2.2.5 IXP
Description
The main processor is an IXP42x processor manufactured by INTEL. It consists of a
central ARM based processor supported by separate network processor engines for
supporting the Ethernet and USB ports. The IXP runs the application code under
MontaVista Linux. The application code consists of Trunked Site Control, Inter-Blade
Communications, Site Configuration, Fan Control and the LCD menu system.
The network processor also provides support to the DSP. The IXP is connected to
external flash memory that stores the IXP software. Reset of the IXP is performed reset
circuitry monitoring voltage supplies.
Watchdog
The IXP processor has its own internal watchdog.
Fan Control
The IXP performs fan control via Maxim Fan Regulator devices, monitoring the
temperature of the airflow from the transmitter module using a thermistor (RT1). If the
temperature is too high or low, the speed of the fans is adjusted accordingly. Fans are not
allowed to stop during normal operation. Each fan generates a tachometer output allowing
software to detect a fan failure or potential failure by monitoring fan speed. If one fan fails
the speed of the second fan will be increased to compensate.
Analogue Outputs
Two analogue outputs are provided by a dual-channel Digital to Analogue Converter
(U41). They provide analogue outputs to the Facilities Connector to output, for example,
the RSSI level.
Analogue Inputs
The ADC (U56) has eight analogue inputs available, which are currently used to provide
voltage monitoring of the thermistor and the 12V unregulated supply, receive inputs from
the PA header and provide feedback of the analogue outputs.
Digital I/O
A set of shift registers (U10, U11, U15, U16 and U17) is controlled by the IXP via the
CPLD to provide digital I/O to the Facilities Connector as well as internal controls.
Ethernet interface