reflow-oven-control-sw/stm-firmware/rotary-encoder.c

/* Reflow Oven Controller
*
* Copyright (C) 2020  Mario Hüttel <mario.huettel@gmx.net>
*
* This file is part of the Reflow Oven Controller Project.
*
* The reflow oven controller is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* The Reflow Oven Control Firmware 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 the reflow oven controller project.
* If not, see <http://www.gnu.org/licenses/>.
*/

#include <reflow-controller/rotary-encoder.h>
#include <stm-periph/clock-enable-manager.h>
#include <stm-periph/stm32-gpio-macros.h>
#include <helper-macros/helper-macros.h>

static inline void rotary_encoder_setup_pins(void)
{
	rcc_manager_enable_clock(&RCC->AHB1ENR, BITMASK_TO_BITNO(ROTARY_ENCODER_RCC_MASK));
	ROTARY_ENCODER_PORT->MODER &= MODER_DELETE(ROTARY_ENCODER_PIN1) & MODER_DELETE(ROTARY_ENCODER_PIN2);
	ROTARY_ENCODER_PORT->MODER |= ALTFUNC(ROTARY_ENCODER_PIN1) | ALTFUNC(ROTARY_ENCODER_PIN2);
	SETAF(ROTARY_ENCODER_PORT, ROTARY_ENCODER_PIN1, ROTARY_ENCODER_PORT_ALTFUNC);
	SETAF(ROTARY_ENCODER_PORT, ROTARY_ENCODER_PIN2, ROTARY_ENCODER_PORT_ALTFUNC);
}

void rotary_encoder_setup(void)
{
	rcc_manager_enable_clock(&RCC->APB1ENR, BITMASK_TO_BITNO(ROTARY_ENCODER_TIMER_RCC_MASK));
	rotary_encoder_setup_pins();

	ROTARY_ENCODER_TIMER->ARR = 0xFFFF;
	ROTARY_ENCODER_TIMER->CNT = 0;
	ROTARY_ENCODER_TIMER->CR2 = 0;
	ROTARY_ENCODER_TIMER->SMCR = TIM_SMCR_SMS_0 | TIM_SMCR_SMS_1;
	ROTARY_ENCODER_TIMER->CCMR1 = TIM_CCMR1_CC1S_0 | TIM_CCMR1_CC2S_0;
	ROTARY_ENCODER_TIMER->CCER = TIM_CCER_CC1P | TIM_CCER_CC2P;
	ROTARY_ENCODER_TIMER->PSC = 0;
	ROTARY_ENCODER_TIMER->CR1 = TIM_CR1_CEN;
}

uint32_t rotary_encoder_get_abs_val(void)
{
	return (uint32_t)ROTARY_ENCODER_TIMER->CNT;
}

int32_t rotary_encoder_get_change_val(void)
{
	static uint32_t last_val = 0;
	uint32_t val;
	int32_t diff;

	val = rotary_encoder_get_abs_val();

	diff = val - last_val;

	if (val > last_val) {
		if (diff > (0xFFFF/2))
			diff = -(last_val + 0x10000-val);
	} else {
		if (ABS(diff) > (0xFFFF/2))
			diff = 0x10000 - last_val + val;
	}

	last_val = val;

	return diff;
}

void rotary_encoder_stop(void)
{
	ROTARY_ENCODER_TIMER->CR1 = 0;
	ROTARY_ENCODER_TIMER->CR2 = 0;
	ROTARY_ENCODER_TIMER->ARR = 0;
	rcc_manager_disable_clock(&RCC->APB1ENR, BITMASK_TO_BITNO(ROTARY_ENCODER_TIMER_RCC_MASK));
	rcc_manager_disable_clock(&RCC->AHB1ENR, BITMASK_TO_BITNO(ROTARY_ENCODER_RCC_MASK));
}

void rotary_encoder_zero(void)
{
	ROTARY_ENCODER_TIMER->CNT = 0UL;
}