L9803 STMicroelectronics, L9803 Datasheet - Page 24

• Manufacturer Part Number: L9803
• Description: Super Smart Power Motor Driver With 8-bit Mcu, Ram, Eeprom, Adc, Wdg, Timers, Pwm And H-bridge Driver
• Manufacturer: STMicroelectronics

Clocks, Reset, Interrupts & Power saving modes
3.5
3.5.1
24/126
Reset Value:0000 0000 (00h)
b0 - Slow Mode Select
0- Normal mode - Oscillator frequency / 2 (Reset state)
1- Slow mode (Bits b1 and b2 define the prescaler factor)
b1, b2 - CPU clock prescaler for Slow Mode
b3, b4 - External Interrupt Option
The selection issued from b3/b4 combination is applied to PA[0]..PA[7],PB0,PB1 external
interrupt. The selection can be made only if I bit in CC register is reset (interrupt enabled).
b3, b4 can be written only when the Interrupt Mask (I) of the CC (Condition Code) register is
set to 1.
b5,b6,b7 = not used
Reset
Introduction
There are four sources of Reset:
The Reset Service Routine vector is located at address FFFEh-FFFFh.
b4
b2
0
1
0
1
0
1
0
1
–
–
–
–
-
NRESET pin (external source)
Power-On Reset / Low Voltage Detection (Internal source)
WATCHDOG (Internal Source)
SAFEGUARD (Internal source)
b1
b3
0
0
1
1
0
0
1
1
-
Oscillator frequency / 4
Oscillator frequency / 8
Oscillator frequency / 16
Oscillator frequency / 32
Falling edge and low level (Reset state)
Falling edge only
Rising edge only
Rising and Falling edge
-
b4
b3
Option
Option
b2
b1
b0
L9803