Low Power in PICMICRO

1. 704 NWF Low Power Features of the nanoWatt Family Devices

8. Clock System: PIC16 Prescaler Timer1 Oscillator Primary Oscillator (EC, RC, LP, XT, HS) Timer 1 Enable To CPU and Peripherals To Timer 1 INTRC (31kHz) Post- 1:2 scaler 1:4 1:8 1:16 1:32 1:64 INTOSC (8 MHz) OSCCON CONFIG1 & OSCCON WDTPS WDT / TMR0 Multiplexer 1ms - 2.1sec 32us FS Clock Monitor Bias Prescaler 1:32 to 1:65536

9. Clock System: PIC18 Prescaler Timer1 Oscillator Primary Oscillator (RC, EC, LP, XT, HS, HSPLL) IDLE Mode Timer 1 Enable To CPU Clock To Peripherals To Timer 1 INTRC (31kHz) Post- 1:2 scaler 1:4 1:8 1:16 1:32 1:64 INTOSC (8 MHz) CONFIG1H & OSCCON 32us 1:125 4ms WDT Time-out FS Clock Monitor WDT Postscaler 1:1 to 1:32768 Bias

22. Clock System: OSCCON Register IDLEN Controls CPU clocking (PIC18 Only) IRCF<2:0> Selects tap from INTOSC Postscaler OSTS =1 if Primary clock is currently providing the system clock IOFS =1 if INTOSC (8 MHz) output is stable SCS<1:0> Selects the power managed mode clock source

38. FSCM: How Does It Work? Sample Clock (INTRC/64 - Clear) Peripheral Clock (Clock/4 - Set) CM F/F Q Output OSCFIF Oscillator Failure Failure Detected Set OSCFIF INTRC (32 us)  64 Set Q Clear !Q Peripheral clock Clock Monitor F/F ~2ms period CM F/F Tested CM F/F Tested CM F/F Tested

49. Clock System: PIC18 Prescaler Timer1 Oscillator Primary Oscillator (RC, EC, LP, XT, HS, HSPLL) IDLE Mode Timer 1 Enable To CPU Clock To Peripherals To Timer 1 INTRC (31kHz) Post- 1:2 scaler 1:4 1:8 1:16 1:32 1:64 INTOSC (8 MHz) CONFIG1H & OSCCON 32us 1:125 4ms WDT Time-out FS Clock Monitor WDT Postscaler 1:1 to 1:32768 Bias

61. Power Managed Modes

83. 704 NWF Low Power Features of the nanoWatt Family Devices