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https://github.com/eddyem/STM8_samples.git
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48 lines
1.7 KiB
C
48 lines
1.7 KiB
C
/*
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* noicegen.c
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*
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* Copyright 2014 Edward V. Emelianoff <eddy@sao.ru>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
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* MA 02110-1301, USA.
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*/
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#include "noicegen.h"
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void configure_timers(){
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/**** TIMERS TIM1 - 16MHz, TIM2 - 1MHz ****/
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TIM1_PSCRH = 0; // this timer have 16 bit prescaler
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TIM1_PSCRL = 0; // LSB should be written last as it updates prescaler
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TIM2_PSCR = 4;
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// Timer1 is PWM sound level generator
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// Timer2 runs with F to change voltage level (F - frequency of sound)
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TIM1_ARRH = 0;
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TIM1_ARRL = 255;
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TIM1_CCR1H = 0; TIM1_CCR1L = 127; // default: 50%
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// channel 1 generates PWM pulses
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TIM1_CCMR1 = 0x60; // OC1M = 110b - PWM mode 1 ( 1 -> 0)
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//TIM1_CCMR1 = 0x70; // OC1M = 111b - PWM mode 2 ( 0 -> 1)
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TIM1_CCER1 = 1; // Channel 1 is on. Active is high
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//TIM1_CCER1 = 3; // Channel 1 is on. Active is low
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// default period: 33ms (30Hz)
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TIM2_ARRH = 128; TIM2_ARRL = 232; // 0x80E8 = 33000
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// interrupts: update for timer 2, none for timer 1
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TIM1_IER = 0;
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TIM2_IER = TIM_IER_UIE;
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// enable PWM output for timer1
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TIM1_BKR |= 0x80; // MOE
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}
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