SAA1305T
FEATURES
· 8 accurate Schmitt trigger inputs with clamp circuits
· Very low quiescent current
· Reset generator circuit
· Changed information output
· On/off output to control a regulator IC which supplies the
microcontroller
· 32.768 kHz RC oscillator and/or a 32.768 kHz crystal
oscillator
· No delayed reset needed (start-up behaviour oscillator
fixed by internal logic)
· Watchdog timer function
· Blinking LED oscillator with drive circuit for LED
· Watch function.
GENERAL DESCRIPTION
The SAA1305T is an on/off logic IC, intended for use in car
radios to interface between a microcontroller and various
input signals such as ignition, low supply detection, on/off
key and external control signals.
The SAA1305T can replace an existing on/off logic built-up
with discrete components.
The SAA1305T contains 8 inputs with accurate Schmitt
triggers and clamp circuits. The main function of this IC is
an intelligent I/O expander with 2 modes of operation:
1. Normal I/O expander: the microcontroller (master) is
running and the SAA1305T acts like a slave.
2. Sleep mode of the total application: the microcontroller
is stopped and the SAA1305T acts like a master.
During an event, the microcontroller is awakened.
The communication with the IC is performed via the
I2C-bus (400 kHz). Extra functions of the SAA1305T are:
· LED blinker circuit
· One-day watch
· Watchdog timer.
