STM8AL3146 Timer not producing calculated PWM frequency at output timer channel
Hi all,
please suggest some solution for this,
I am trying to produce 14.7khz PWM signal with below timer1 configuration for 16Mhz clock frequency and i am getting 14.53Khz to 14.83Khz.
Why am i getting this frequency variation. Is ST timer can not produce exact output PWM frequency?
F_CK_PSC(prescaler frequency) is 16Mhz and Timer1 configuration are as below.
More than 1 timer channel have been used and all shows same frequency variation
// enable peripheral clock
CLK_PCKENR2_bit.PCKEN21 = 1;
// PWM Mode 1 (output low while TIM1_CNT < TIM1_CCR1); Output-Compare preload enable; CC1 output
TIM1_CCMR1 = 0x68;
// PWM Mode 1 (output low while TIM1_CNT < TIM1_CCR2); Output-Compare preload enable; CC2 output
TIM1_CCMR2 = 0x68;
// PWM Mode 1 (output low while TIM1_CNT < TIM1_CCR3); Output-Compare preload enable; CC3 output
TIM1_CCMR3 = 0x68;
// Enable Timer 1 Ch 1+2 output
TIM1_CCER1 = 0x11;
// Enable Timer 1 Ch 3+4 output
TIM1_CCER2 = 0x01;
// Main output enable
TIM1_BKR = 0x81;
// Set auto-reload register and clock divider to get a base-frequency of 14.7 kHz
// Calculated by: T_Interrupt = (ARR+1)/f_timer => ARR = 1087; PSCR = 0
// Note: Maximum ARR , as CCR needs to be lower than ARR
// Count 0x043F for 14.7KHz
// Count 0x087F for 7.35KHz
//TIM1_ARRH = 0x04;
//TIM1_ARRL = 0x3F;
// Prescalar is 0
TIM1_PSCRH = 0x00;
TIM1_PSCRL = 0x00;
// Generate update request for setting new register values
TIM1_EGR_bit.UG = 1;
// TIM1_ARR unbuffered; Edge-aligned mode; up-counter direction;
// Counter not stopping on update event; Counter enabled
TIM1_CR1 = 0x01;
let me know if more information is needed.