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Intel
IQ80315 I/O Processor Evaluation Platform
2.10.1.1
Real Time Clock—ST Microelectronics* M41ST84W
An ST Microelectronics* M41ST84W Real-Time Clock chip is used to keep time on the IQ80315
CRB. This real time clock (RTC) chip uses an external CR2032 lithium cell battery, has 44 bytes of
onboard storage, and provides a square-wave signal output for a buzzer or speaker. The battery life
of the CR2032 cell exceeds 10 years.
The RTC square-wave output can be programmed to generate 15 discrete frequencies between
1 Hz and 32 KHz. The square-wave output is enabled or disabled by writing to a register in the
RTC. The square-wave output is buffered and directed to either the buzzer or speaker output by a
3-pin jumper.
The IQ80315 CRB supports both a speaker and a buzzer for design flexibility. The buzzer is useful
when the board is used without an ATX chassis and the speaker when used with a chassis.
2.10.1.2
Audio Buzzer
An RDI Electronics* DMT-1206-SMT buzzer is mounted on the CRB board. It generates a tone
when the RTC square-wave signal is activated and connected to the buzzer. The default condition is
off. A DIP switch selects low or high buzzer volume. The buzzer frequency range is approximately
500 Hz to 3 KHz.
2.10.1.3
Chassis Speaker
A standard ATX chassis has a speaker mounted on the front panel. The speaker is connected to the
motherboard speaker drive electronics through a cable and a standard speaker connector. See
Section 2.11
high speaker volume.
2.10.1.4
Watchdog Timer
A watchdog timer is built into the M41ST84W real time clock. The watchdog timer is inactive on
reset. Software can enable and disable the watchdog timer and configure the time-out period. The
watchdog countdown timer is reset by writing to a register in the RTC.
2.10.1.5
Fan Control—Dual Maxim* MAX6651s
Two Maxim* MAX6651 Fan Control ICs (hereafter "6651") provide control of up to eight chassis
fans. Two fan controllers are provided to allow using different fans on the front and rear. Each 6651
fan controller monitors the tach outputs of up to four fans. The 6651 controls fan-speed by
monitoring the tach0 fan signal and adjusting the fan control output to maintain the tach0 input at
the programmed speed. For this reason, each 6651 must control similar fans.
The fan control connectors are standard PC type 3 pin Molex* connectors. A single MOSFET is
used to gate motor power for four fans, and a diode is used to prevent over-voltage conditions.
2.10.1.6
Serial 2 Kbyte EEPROM—MicroChip* 24LC16B
The Serial EEPROM has 2 Kbytes of non-volatile storage and is used to store the 80314
configuration parameters and for general non-volatile storage needs. After reset, the 80314 device
reads the serial EEPROM and updates the 80314 configuration registers prior to booting.
22
for a description of the speaker connector and pinout. A DIP switch selects low or
®
Intel
IQ80315 I/O Processor Evaluation Platform Board Manual
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