Fast PWM - Lead Acid battery charger

납축전지 회로 설계중
CLK = 8M --> PWM Hz = 32 KHz
CLK = 10M --> PWM Hz = 39 KHz 

LeadAcidBatCharger_LCDxxx.zip

 

// For ATmega8, FastPWM mode is possible only 8bit timer/counter2 & 16bit T/C

// in 8bit T/C2 mode - Output pin = PB4 OC2 (MISO), duty = OCR2

// the Output Compare (OC2) is cleared on the Compare

// Match between TCNT2 and OCR2, and set at BOTTOM

// DDRB=0x08;

// PORTB=0x08;

// TCCR2=0b01101100 (FastPWM, COM21,COM20=[1 0];

// OCR2 = 0 ; duty = 0%

// in 16bit timer/counter mode - Output pin = PB1 OC1A, duty = OCR1A

// Use this mode in order to use PB1 as PB4 is assigned to SD card

void SetupFastPWM(void){

// PWM Hz = clk/[N*(1+TOP)] = 8000000/[1*(1+255)] = 31,250 Hz

DDRB = 0x02;

PORTB = 0x02;

// (COM1A[10]:out chan=A, WGM1310[0101]:FastPWM 8Bit)

// TCCR1A = COM1A1 COM1A0 COM1B1 COM1B0 FOC1A FOC1B WGM11 WGM10

TCCR1A = 0b10000001;  (COM1A=10 for OCR1A out pin, WGM11.10=01)

// TCCR1B = ICNC1 ICES1 - WGM13 WGM12 CS12 CS11 CS10

TCCR1B = 0b00010001;  (WGM13.12=01, prescale=1)

OCR1A = 0;    duty = 0

}