IR-controller/with_opencm3/hardware_ini.c

/*
 * hardware_ini.c - functions for HW initialisation
 *
 * Copyright 2014 Edward V. Emelianov <eddy@sao.ru, edward.emelianoff@gmail.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301, USA.
 */

/*
 * All hardware-dependent initialisation & definition should be placed here
 * and in hardware_ini.h
 *
 */

#include "main.h"
#include "hardware_ini.h"
#include "onewire.h"

#define ADC_CHANNELS_NUMBER    10
/*
 * Due to inconvenient pins position on STM32F103VxT6 I had to make this strange location:
 * my channel #   ->   ADC1/2 channel #
 * 0 -> 9    PB1
 * 1 -> 8    PB0
 * 2 -> 15   PC5
 * 3 -> 14   PC4
 * 4 -> 7    PA7
 * 5 -> 6    PA6
 * 6 -> 5    PA5
 * 7 -> 4    PA4
 * U36 -> 1  PA1
 * U10 -> 0  PA0
 */
uint8_t adc_channel_array[16] = {9,8,15,14,7,6,5,4,1,0};
volatile uint16_t ADC_value[ADC_CHANNELS_NUMBER]; // ADC DMA value

/*
 * Configure SPI ports
 */
/*
 *      SPI1 remapped:
 * SCK  - PB3
 * MISO - PB4
 * MOSI - PB5
 */
void SPI1_init(){
	// enable AFIO & other clocking
	rcc_peripheral_enable_clock(&RCC_APB2ENR,
			RCC_APB2ENR_SPI1EN | RCC_APB2ENR_AFIOEN | RCC_APB2ENR_IOPBEN);
	// remap SPI1 (change pins from PA5..7 to PB3..5); also turn off JTAG
	gpio_primary_remap(AFIO_MAPR_SWJ_CFG_JTAG_OFF_SW_OFF, AFIO_MAPR_SPI1_REMAP);
	// SCK, MOSI - push-pull output
	gpio_set_mode(GPIO_BANK_SPI1_RE_SCK, GPIO_MODE_OUTPUT_50_MHZ,
		GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_SPI1_RE_SCK);
	gpio_set_mode(GPIO_BANK_SPI1_RE_MOSI, GPIO_MODE_OUTPUT_50_MHZ,
		GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_SPI1_RE_MOSI);
	// MISO - opendrain in
	gpio_set_mode(GPIO_BANK_SPI1_RE_MISO, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO_SPI1_RE_MISO);
	spi_reset(SPI1);
	/* Set up SPI in Master mode with:
	 * Clock baud rate: 1/128 of peripheral clock frequency (APB2, 72MHz)
	 * Clock polarity: Idle High
	 * Clock phase: Data valid on 2nd clock pulse
	 * Data frame format: 8-bit
	 * Frame format: MSB First
	 */
	spi_init_master(SPI1, SPI_CR1_BAUDRATE_FPCLK_DIV_128, SPI_CR1_CPOL_CLK_TO_1_WHEN_IDLE,
		SPI_CR1_CPHA_CLK_TRANSITION_2, SPI_CR1_DFF_8BIT, SPI_CR1_MSBFIRST);
	nvic_enable_irq(NVIC_SPI1_IRQ); // enable SPI interrupt
}

/*
 *     SPI2:
 * SCK  - PB13
 * MISO - PB14
 * MOSI - PB15
 */
void SPI2_init(){
	// turn on clocking
	//rcc_periph_clock_enable(RCC_SPI2 | RCC_GPIOB);
	rcc_peripheral_enable_clock(&RCC_APB1ENR, RCC_APB1ENR_SPI2EN);
	rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_AFIOEN | RCC_APB2ENR_IOPBEN);
	// SCK, MOSI - push-pull output
	gpio_set_mode(GPIO_BANK_SPI2_SCK, GPIO_MODE_OUTPUT_50_MHZ,
		GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_SPI2_SCK);
	gpio_set_mode(GPIO_BANK_SPI2_MOSI, GPIO_MODE_OUTPUT_50_MHZ,
		GPIO_CNF_OUTPUT_ALTFN_PUSHPULL, GPIO_SPI2_MOSI);
	// MISO - opendrain in
	gpio_set_mode(GPIO_BANK_SPI2_MISO, GPIO_MODE_INPUT, GPIO_CNF_INPUT_FLOAT, GPIO_SPI2_MISO);
	spi_reset(SPI2);
	/* Set up SPI in Master mode with:
	 * Clock baud rate: 1/64 of peripheral clock frequency (APB1, 36MHz)
	 * Clock polarity: Idle High
	 * Clock phase: Data valid on 2nd clock pulse
	 * Data frame format: 8-bit
	 * Frame format: MSB First
	 */
	spi_init_master(SPI2, SPI_CR1_BAUDRATE_FPCLK_DIV_64, SPI_CR1_CPOL_CLK_TO_1_WHEN_IDLE,
		SPI_CR1_CPHA_CLK_TRANSITION_2, SPI_CR1_DFF_8BIT, SPI_CR1_MSBFIRST);
	nvic_enable_irq(NVIC_SPI2_IRQ); // enable SPI interrupt
}

/**
 * GPIO initialisaion: clocking + pins setup
 */
void GPIO_init(){
/*	rcc_periph_clock_enable(RCC_AFIO);
	rcc_periph_clock_enable(RCC_SPI1);
	rcc_periph_clock_enable(RCC_GPIOC);*/
	rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_IOPAEN |
			RCC_APB2ENR_IOPBEN | RCC_APB2ENR_IOPCEN | RCC_APB2ENR_IOPDEN |
			RCC_APB2ENR_IOPEEN);
	// USB_DISC: push-pull
	gpio_set_mode(USB_DISC_PORT, GPIO_MODE_OUTPUT_2_MHZ,
				GPIO_CNF_OUTPUT_PUSHPULL, USB_DISC_PIN);
	// USB_POWER: open drain, externall pull down with R7 (22k)
	gpio_set_mode(USB_POWER_PORT, GPIO_MODE_INPUT,
				GPIO_CNF_INPUT_FLOAT, USB_POWER_PIN);
	// AD7794 addr + en
	gpio_set_mode(ADC_ADDR_PORT, GPIO_MODE_OUTPUT_2_MHZ,
				GPIO_CNF_OUTPUT_PUSHPULL, ADC_ADDR_MASK | ADC_EN_PIN); // ADDRESS: PD10..12; EN: PD13
	gpio_clear(ADC_ADDR_PORT, ADC_ADDR_MASK | ADC_EN_PIN); // clear address & turn switch off
}

/*
 * SysTick used for system timer with period of 1ms
 */
void SysTick_init(){
	systick_set_clocksource(STK_CSR_CLKSOURCE_AHB_DIV8); // Systyck: 72/8=9MHz
	systick_set_reload(8999); // 9000 pulses: 1kHz
	systick_interrupt_enable();
	systick_counter_enable();
}

/**
 * Turn on ADC DMA for filling temperatures buffer
 */
void adc_dma_on(){
	// first configure DMA1 Channel1 (ADC1)
	nvic_disable_irq(NVIC_DMA1_CHANNEL1_IRQ);
	dma_channel_reset(DMA1, DMA_CHANNEL1);
	DMA1_CPAR1 = (uint32_t) &(ADC_DR(ADC1));
	DMA1_CMAR1 = (uint32_t) ADC_value;
	DMA1_CNDTR1 = ADC_CHANNELS_NUMBER;
	DMA1_CCR1 = DMA_CCR_MINC | DMA_CCR_PSIZE_16BIT | DMA_CCR_MSIZE_16BIT
			| DMA_CCR_CIRC | DMA_CCR_PL_HIGH | DMA_CCR_EN;
	adc_enable_dma(ADC1);
	adc_power_on(ADC1);
	/*
	dma_set_peripheral_address(DMA1, DMA_CHANNEL1, (uint32_t) &(ADC_DR(ADC1)));
	dma_set_memory_address(DMA1, DMA_CHANNEL1, (uint32_t) ADC_value);
	dma_set_number_of_data(DMA1, DMA_CHANNEL1, ADC_CHANNELS_NUMBER);
	dma_set_read_from_peripheral(DMA1, DMA_CHANNEL1);
	dma_enable_memory_increment_mode(DMA1, DMA_CHANNEL1);
	dma_disable_peripheral_increment_mode(DMA1, DMA_CHANNEL1);
	dma_set_peripheral_size(DMA1, DMA_CHANNEL1, DMA_CCR_PSIZE_16BIT);
	dma_set_memory_size(DMA1, DMA_CHANNEL1, DMA_CCR_MSIZE_16BIT);
	dma_enable_circular_mode(DMA1, DMA_CHANNEL1);
	dma_set_priority(DMA1, DMA_CHANNEL1, DMA_CCR_PL_HIGH);
	dma_disable_transfer_error_interrupt(DMA1, DMA_CHANNEL1);
	dma_disable_transfer_complete_interrupt(DMA1, DMA_CHANNEL1);
	dma_enable_channel(DMA1, DMA_CHANNEL1);
	*/
}

void ADC_init(){
	rcc_peripheral_enable_clock(&RCC_APB2ENR, RCC_APB2ENR_ADC1EN); // enable clocking
	rcc_periph_clock_enable(RCC_ADC1);
	rcc_set_adcpre(RCC_CFGR_ADCPRE_PCLK2_DIV4);
	rcc_periph_clock_enable(RCC_GPIOA | RCC_GPIOB | RCC_GPIOC); // clocking for ADC ports
	// channels 4-7: PA7-PA4 (ADC IN 4..7); U10 (PA0); U36 (PA1)
	gpio_set_mode(GPIOA, GPIO_MODE_INPUT, GPIO_CNF_INPUT_ANALOG, GPIO4|GPIO5|GPIO6|GPIO7|GPIO1|GPIO0);
	// channels 0,1: PB1, PB0 (ADC IN 8, 9)
	gpio_set_mode(GPIOB, GPIO_MODE_INPUT, GPIO_CNF_INPUT_ANALOG, GPIO0|GPIO1);
	// channels 2,3: PC5, PC4 (ADC IN14, 15)
	gpio_set_mode(GPIOC, GPIO_MODE_INPUT, GPIO_CNF_INPUT_ANALOG, GPIO4|GPIO5);

	// Make sure the ADC doesn't run during config
	adc_off(ADC1);
	rcc_periph_clock_enable(RCC_DMA1);

	// Configure ADC as continuous scan mode with DMA
	adc_set_dual_mode(ADC_CR1_DUALMOD_IND); // ADC_InitStructure.ADC_Mode = ADC_Mode_Independent;
	adc_enable_scan_mode(ADC1); // ADC_InitStructure.ADC_ScanConvMode = ENABLE;
	adc_set_continuous_conversion_mode(ADC1); // ADC_InitStructure.ADC_ContinuousConvMode = ENABLE;
	adc_disable_external_trigger_regular(ADC1); // ADC_InitStructure.ADC_ExternalTrigConv = ADC_ExternalTrigConv_None;
	adc_set_right_aligned(ADC1); // ADC_InitStructure.ADC_DataAlign = ADC_DataAlign_Right;
	adc_set_sample_time_on_all_channels(ADC1, ADC_SMPR_SMP_239DOT5CYC); // ADC_SampleTime_239Cycles5
	//adc_set_sample_time(ADC1, ADC_CHANNEL8, ADC_SMPR_SMP_239DOT5CYC); // ADC_RegularChannelConfig(ADC1, ADC_Channel_8, 1, ADC_SampleTime_239Cycles5);

	adc_dma_on();
}

/**
 * Starts ADC calibration & after it runs ADC in continuous conversion mode
 * First call ADC_init(), than wait a little and call this function
 */
void ADC_calibrate_and_start(){
	adc_set_regular_sequence(ADC1, ADC_CHANNELS_NUMBER, adc_channel_array);
	adc_reset_calibration(ADC1);
	adc_calibration(ADC1);
	adc_start_conversion_regular(ADC1); // ADC_SoftwareStartConvCmd(ADC1, ENABLE);
	adc_start_conversion_direct(ADC1);
}

/**
 * get shutter voltage in value of U*100
 * 3.3V == 4096 ADU, 36V comes to ADC in through resistor divider 4.7k:56k, so
 * U36(V/100) = Uadc(ADU) * 607/47 * 33/40960 * 100 = Uadc(ADU) * 20031 / 19251
 * ==> approximately this is equal to val*26/25 or val + val/25
 */
int shutter_voltage(){
	int val = SHUTTER_SENSE_VALUE;
	val += val/25;
	return val;
}

/**
 * get power voltage in value of U*100
 * 3.3V == 4096 ADU, 10..12V comes to ADC in through resistor divider 4.7k:12k, so
 * U10(V/100) = Uadc(ADU) * 167/47 * 33/40960 * 100 = Uadc(ADU) * 5511 / 19251
 * ==> approximately this is equal to val*2/7
 */
int power_voltage(){
	int val = POWER_SENSE_VALUE * 2;
	val /= 7;
	return val;
}

/**
 * Resistance of TRD
 * @param num - number of sensor
 * @return R*100
 * we measure
 */
int TRD_value(uint8_t num){
	uint32_t v = ADC_value[num];
	uint32_t r = 100000 * v;
	r /= (uint32_t)(4096 - v);
	return (int) r;
}


uint16_t tim2_buff[TIM2_DMABUFF_SIZE];
uint16_t tim2_inbuff[TIM2_DMABUFF_SIZE];
int tum2buff_ctr = 0;
uint8_t ow_done = 1;
/**
 * this function sends bits of ow_byte (LSB first) to 1-wire line
 * @param ow_byte - byte to convert
 * @param Nbits   - number of bits to send
 * @param ini     - 1 to zero counter
 */
uint8_t OW_add_byte(_U_ uint8_t ow_byte, _U_ uint8_t Nbits, _U_ uint8_t ini){
	uint8_t i, byte;
	if(ini) tum2buff_ctr = 0;
	if(Nbits == 0) return 0;
	if(Nbits > 8) Nbits = 8;
	for(i = 0; i < Nbits; i++){
		if(ow_byte & 0x01){
			byte = OW_1;
		}else{
			byte = OW_0;
		}
		tim2_buff[tum2buff_ctr++] = byte;
		if(tum2buff_ctr == TIM2_DMABUFF_SIZE) return 0; // avoid buffer overflow
		ow_byte = ow_byte >> 1;
	}
//	print_int(tum2buff_ctr, lastsendfun);
//	MSG(" bytes in send buffer\n");
	return 1;
}

/**
 * Adds Nbytes bytes 0xff  for reading sequence
 */
uint8_t OW_add_read_seq(uint8_t Nbytes){
	uint8_t i;
	if(Nbytes == 0) return 0;
	Nbytes *= 8; // 8 bits for each byte
	for(i = 0; i < Nbytes; i++){
		tim2_buff[tum2buff_ctr++] = 1;
		if(tum2buff_ctr == TIM2_DMABUFF_SIZE) return 0;
	}
#ifdef EBUG
	print_int(tum2buff_ctr, lastsendfun);
	MSG(" bytes in send buffer\n");
#endif
	return 1;
}

/**
 * Fill output buffer with data from 1-wire
 * @param start_idx - index from which to start (bit number)
 * @param N         - data length (in **bytes**)
 * @outbuf          - where to place data
 */
void read_from_OWbuf(_U_ uint8_t start_idx, _U_ uint8_t N, _U_ uint8_t *outbuf){
	uint8_t i, j, last = start_idx + N * 8, byte;
	if(last >= TIM2_DMABUFF_SIZE) last = TIM2_DMABUFF_SIZE;
	for(i = start_idx; i < last;){
		byte = 0;
		for(j = 0; j < 8; j++){
			byte >>= 1;
#ifdef EBUG
			print_int(tim2_inbuff[i], lastsendfun);
			MSG(" ");
#endif
			if(tim2_inbuff[i++] < OW_READ1)
				byte |= 0x80;
		}
		*outbuf++ = byte;
#ifdef EBUG
		MSG("readed \n");
#endif
	}
}
// there's a mistake in opencm3, so redefine this if needed (TIM_CCMR2_CC3S_IN_TI1 -> TIM_CCMR2_CC3S_IN_TI4)
#ifndef TIM_CCMR2_CC3S_IN_TI4
#define TIM_CCMR2_CC3S_IN_TI4		(2)
#endif
void init_ow_dmatimer(){ // tim2_ch4 - PA3, no remap
	gpio_set_mode(GPIOA, GPIO_MODE_OUTPUT_50_MHZ,
			GPIO_CNF_OUTPUT_ALTFN_OPENDRAIN, GPIO3);
	rcc_periph_clock_enable(RCC_TIM2);
	rcc_periph_clock_enable(RCC_DMA1);
	timer_reset(TIM2);
	// timers have frequency of 1MHz -- 1us for one step
	// 36MHz of APB1
	timer_set_mode(TIM2, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP);
	// 72MHz div 72 = 1MHz
	TIM2_PSC = 71;  // prescaler is (div - 1)
	TIM2_CR1 &= ~(TIM_CR1_OPM | TIM_CR1_UDIS); // continuous mode & enable update events
	TIM2_CR1 |= TIM_CR1_ARPE; // changing period immediately
	TIM2_ARR = OW_BIT; // default period of timer
	// PWM_OUT: TIM2_CH4; capture: TIM2_CH3
	// PWM edge-aligned mode & enable preload for CCR4, CC3 takes input from TI4
	TIM2_CCMR2 = TIM_CCMR2_OC4M_PWM1 | TIM_CCMR2_OC4PE | TIM_CCMR2_CC3S_IN_TI4;
	TIM2_CCR4 = 0; // set output value to 1 by clearing CCR4
	TIM2_EGR = TIM_EGR_UG; // update values of ARR & CCR4
	// set low polarity for CC4, high for CC4 & enable CC4 out and CC3 in
	TIM2_CCER = TIM_CCER_CC4P | TIM_CCER_CC4E | TIM_CCER_CC3E;

	// TIM2_CH4 - DMA1, channel 7
	dma_channel_reset(DMA1, DMA_CHANNEL7);
	DMA1_CCR7 = DMA_CCR_DIR | DMA_CCR_MINC | DMA_CCR_PSIZE_16BIT | DMA_CCR_MSIZE_16BIT
			| DMA_CCR_TEIE | DMA_CCR_TCIE | DMA_CCR_PL_HIGH;
	/*
	DMA1_CCR7 |= DMA_CCR_DIR; // dma_set_read_from_memory(DMA1, DMA_CHANNEL7);
	DMA1_CCR7 |= DMA_CCR_MINC; // dma_enable_memory_increment_mode(DMA1, DMA_CHANNEL7);
	//dma_disable_peripheral_increment_mode(DMA1, DMA_CHANNEL7);
	DMA1_CCR7 |= DMA_CCR_PSIZE_16BIT; // dma_set_peripheral_size(DMA1, DMA_CHANNEL7, DMA_CCR_PSIZE_16BIT);
	DMA1_CCR7 |= DMA_CCR_MSIZE_16BIT; // dma_set_memory_size(DMA1, DMA_CHANNEL7, DMA_CCR_MSIZE_16BIT);
	DMA1_CCR7 |= DMA_CCR_TEIE; // dma_enable_transfer_error_interrupt(DMA1, DMA_CHANNEL7);
	DMA1_CCR7 |= DMA_CCR_TCIE; // dma_enable_transfer_complete_interrupt(DMA1, DMA_CHANNEL7);
	*/
	nvic_enable_irq(NVIC_DMA1_CHANNEL7_IRQ); // enable dma1_channel7_isr
}

void run_dmatimer(){
	ow_done = 0;
	adc_disable_dma(ADC1); // turn off DMA & ADC
	adc_off(ADC1);
	DMA1_IFCR = DMA_ISR_TEIF7|DMA_ISR_HTIF7|DMA_ISR_TCIF7|DMA_ISR_GIF7 |
		DMA_ISR_TEIF1|DMA_ISR_HTIF1|DMA_ISR_TCIF1|DMA_ISR_GIF1; // clear flags

	//init_ow_dmatimer();
/*
	// TIM2_CH4 - DMA1, channel 7
	dma_channel_reset(DMA1, DMA_CHANNEL7);
	dma_set_read_from_memory(DMA1, DMA_CHANNEL7);
	dma_enable_memory_increment_mode(DMA1, DMA_CHANNEL7);
	dma_disable_peripheral_increment_mode(DMA1, DMA_CHANNEL7);
	dma_set_peripheral_size(DMA1, DMA_CHANNEL7, DMA_CCR_PSIZE_16BIT);
	dma_set_memory_size(DMA1, DMA_CHANNEL7, DMA_CCR_MSIZE_16BIT);
	dma_enable_transfer_error_interrupt(DMA1, DMA_CHANNEL7);
	dma_enable_transfer_complete_interrupt(DMA1, DMA_CHANNEL7);
	*/
	DMA1_CCR7 &= ~DMA_CCR_EN; // disable (what if it's enabled?) to set address
	DMA1_CPAR7 = (uint32_t) &(TIM_CCR4(TIM2)); // dma_set_peripheral_address(DMA1, DMA_CHANNEL7, (uint32_t) &(TIM_CCR4(TIM2)));
	DMA1_CMAR7 = (uint32_t) tim2_buff; // dma_set_memory_address(DMA1, DMA_CHANNEL7, (uint32_t)tim2_buff);
	DMA1_CNDTR7 = tum2buff_ctr;//dma_set_number_of_data(DMA1, DMA_CHANNEL7, tum2buff_ctr);
	// TIM2_CH4 - DMA1, channel 7
	dma_channel_reset(DMA1, DMA_CHANNEL1);
	DMA1_CCR1 = DMA_CCR_MINC | DMA_CCR_PSIZE_16BIT | DMA_CCR_MSIZE_16BIT
			| DMA_CCR_TEIE | DMA_CCR_TCIE | DMA_CCR_PL_HIGH;
	/*
	dma_set_read_from_peripheral(DMA1, DMA_CHANNEL1);
	dma_enable_memory_increment_mode(DMA1, DMA_CHANNEL1);
	dma_disable_peripheral_increment_mode(DMA1, DMA_CHANNEL1);
	dma_set_peripheral_size(DMA1, DMA_CHANNEL1, DMA_CCR_PSIZE_16BIT);
	dma_set_memory_size(DMA1, DMA_CHANNEL1, DMA_CCR_MSIZE_16BIT);
	dma_enable_transfer_error_interrupt(DMA1, DMA_CHANNEL1);
	dma_enable_transfer_complete_interrupt(DMA1, DMA_CHANNEL1);
	*/
	DMA1_CPAR1 = (uint32_t) &(TIM_CCR3(TIM2)); //dma_set_peripheral_address(DMA1, DMA_CHANNEL1, (uint32_t) &(TIM_CCR3(TIM2)));
	DMA1_CMAR1 = (uint32_t) tim2_inbuff; //dma_set_memory_address(DMA1, DMA_CHANNEL1, (uint32_t) tim2_inbuff);
	DMA1_CNDTR1 = tum2buff_ctr; //dma_set_number_of_data(DMA1, DMA_CHANNEL1, tum2buff_ctr);
	nvic_enable_irq(NVIC_DMA1_CHANNEL1_IRQ);

	DMA1_CCR7 |= DMA_CCR_EN; //dma_enable_channel(DMA1, DMA_CHANNEL7);
	DMA1_CCR1 |= DMA_CCR_EN; //dma_enable_channel(DMA1, DMA_CHANNEL1);

	TIM2_SR = 0; // clear all flags
	TIM2_CR1 &= ~TIM_CR1_OPM; // continuous mode
	TIM2_ARR = OW_BIT; // bit length
	TIM2_EGR = TIM_EGR_UG; // update value of ARR

	TIM2_CR2 &= ~TIM_CR2_CCDS; // timer_set_dma_on_compare_event(TIM2);
	TIM2_CCER |= TIM_CCER_CC3E; // enable input capture
	TIM2_DIER = TIM_DIER_CC4DE | TIM_DIER_CC3DE; // enable DMA events
	// set low polarity, enable cc out & enable input capture
	TIM2_CCER |= TIM_CCER_CC4P | TIM_CCER_CC4E | TIM_CCER_CC3E;
	TIM2_CR1 |= TIM_CR1_CEN; // run timer

}

uint16_t rstat = 0, lastcc3;
void ow_reset(){
	ow_done = 0;
	rstat = 0;
	TIM2_SR = 0; // clear all flags
	TIM2_DIER = 0; // disable timer interrupts
	TIM2_ARR = OW_RESET_TIME; // set period to 1ms
	TIM2_CCR4 = OW_RESET; // zero pulse length
	TIM2_EGR = TIM_EGR_UG; // update values of ARR & CCR4
	TIM2_CR1 |= TIM_CR1_OPM | TIM_CR1_CEN; // we need only single pulse & run timer
	TIM2_SR = 0; // clear update flag generated after timer's running
	TIM2_DIER = TIM_DIER_UIE | TIM_DIER_CC3IE; // generate interrupts on update event & cc
	nvic_enable_irq(NVIC_TIM2_IRQ);
}

void tim2_isr(){
	if(TIM2_SR & TIM_SR_UIF){ // update interrupt
		TIM2_SR &= ~TIM_SR_UIF; // clear flag
		TIM2_DIER = 0; // disable all timer interrupts
		TIM2_CCR4 = 0; // set output value to 1
		TIM2_EGR |= TIM_EGR_UG; // generate update event to change value in CCR4
		TIM2_CR1 &= ~TIM_CR1_CEN;    // timer_disable_counter(TIM2);
		nvic_disable_irq(NVIC_TIM2_IRQ);
		ow_done = 1;
		rstat = lastcc3;
/*		print_int(rstat, lastsendfun);
		MSG("\n");*/
	}
	if(TIM2_SR & TIM_SR_CC3IF){ // we need this interrupt to store CCR3 value
		TIM2_SR = 0; // clear flag (we've manage TIM_SR_UIF before, so can simply do =0)
		lastcc3 = TIM2_CCR3;
		//TIM2_DIER &= ~TIM_DIER_CC3IE; // disable CCR3 interrupts
	}
}


void dma1_channel7_isr(){
	if(DMA1_ISR & DMA_ISR_TCIF7){
		DMA1_IFCR = DMA_IFCR_CTCIF7; // clear flag
		DMA1_CCR7 &= ~DMA_CCR_EN; // disable DMA1 channel 7
		//TIM2_DIER &= ~TIM_DIER_CC4DE;
	}else if(DMA1_ISR & DMA_ISR_TEIF7){
		DMA1_IFCR = DMA_IFCR_CTEIF7;
		MSG("DMA out transfer error\n");
	}
}

void dma1_channel1_isr(){
	//int i;
	if(DMA1_ISR & DMA_ISR_TCIF1) {
		DMA1_IFCR = DMA_IFCR_CTCIF1;
		TIM2_CR1 &= ~TIM_CR1_CEN;    // timer_disable_counter(TIM2);
		//TIM2_DIER &= ~TIM_DIER_CC3DE;
		DMA1_CCR1 &= ~DMA_CCR_EN; // disable DMA1 channel 1
		nvic_disable_irq(NVIC_DMA1_CHANNEL1_IRQ);
		ow_done = 1;
/*		for(i = 0; i < tum2buff_ctr; i++){
			print_int(tim2_inbuff[i], lastsendfun);
			MSG(" ");
		}
		MSG("\n");*/
	}else if(DMA1_ISR & DMA_ISR_TEIF1){
		DMA1_IFCR = DMA_IFCR_CTEIF1;
		MSG("DMA in transfer error\n");
	}
}

uint8_t OW_get_reset_status(){
/*	print_int(rstat, lastsendfun);
	MSG("\n");*/
	if(rstat < OW_PRESENT) return 0; // no devices
	return 1;
}