STFPC320 STMicroelectronics, STFPC320 Datasheet - Page 10

• Manufacturer Part Number: STFPC320
• Description: Front Panel Controller/driver With Standby Power Management And Real-time Clock
• Manufacturer: STMicroelectronics

Functional description
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Functional description
The STFPC320 integrates the supply standby management functionality, remote control
decoder, a 28-bit VFD driver and a real-time clock (RTC). This device is meant to reduce the
standby power consumption of the whole front panel application and also to reduce
hardware/cost by integrating the above mentioned functions in a single chip.
By utilizing the standby function, the host processor and other ICs could be turned off, thus
reducing system power consumption. The STFPC320 is able to wake-up the system when
programmed hotkeys are detected to signal that the full operation of the system is required.
The hotkeys could be entered to the system through the front panel keys or through the
infrared (IR) remote control. STFPC320 supports multiple remote control protocols
decoding by setting the appropriate register.
The integrated 28-bit VFD driver allows display up to 16-digit display. Controlling of the
display is done through writing to a internal RAM. The 4 LED drivers allow indication of
operation of the system. 2-wire serial interface (I
host processor and STFPC320.
The STFPC320 integrates a a low-power Serial RTC with a built-in 32.768kHz oscillator
(external crystal controlled). Eight bytes of the SRAM are used for the clock/calendar
function and are configured in binary coded decimal (BCD) format. An additional 12 bytes of
SRAM provide status/ control of Alarm, Watchdog and Square Wave functions. Addresses
and data are transferred serially via a two line, bi-directional I
address register is incremented automatically after each WRITE or READ data byte.
Functions available to the user include a non-volatile, time-of-day clock/calendar, Alarm
interrupts, Watchdog Timer and programmable Square Wave output. The eight clock
address locations contain the century, year, month, date, day, hour, minute, second and
tenths/hundredths of a second in 24 hour BCD format. Corrections for 28, 29 (leap year -
valid until year 2100), 30 and 31 day months are made automatically.
Reset
Reset is an active low input signal to the STFPC320. Negative pulse input on RESET_N pin
resets the STFPC320. Electrical specifications of this pin are identical to that of the logic
input pin.
Upon power-up, an internal power on reset circuit resets the whole chip. This occurs when
V
time is much lesser than the typical V
RESET_N pin permanently by a pull-up resistor to V
during normal operation. For an initialization on power-up, a power-on-reset in STFPC320 is
sufficient to reset the entire STFPC320.
As soon as the 3.3V supply to the chip is stable, the I
communication.
DD
is ramping up (at approximately 2.7V) and the whole chip is initialized within 4µs. This
DD
ramp-up time. It is recommended to tie the
2
C) completes the interfacing part between
DD
2
C bus of the STFPC320 is ready for
if reset to STFPC320 is not desired
2
C interface. The built-in
STFPC320