80 lines
2.8 KiB
C
80 lines
2.8 KiB
C
/***************************************************************************
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* Copyright (C) 2024 by Silvano Seva IU2KWO *
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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 3 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, see <http://www.gnu.org/licenses/> *
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***************************************************************************/
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#include <interfaces/platform.h>
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#include <peripherals/gpio.h>
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#include <hwconfig.h>
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#include "backlight.h"
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void backlight_init()
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{
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gpioDev_clear(KBD_BKLIGHT);
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gpio_setMode(LCD_BKLIGHT, ALTERNATE | ALTERNATE_FUNC(3));
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/*
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* Configure TIM8 for backlight PWM: Fpwm = 1kHz with 8 bit of resolution.
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* APB2 freq. is 84MHz, but timer runs at twice this frequency.
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* Then: PSC = 655 to have Ftick = 256.097kHz
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* With ARR = 256, Fpwm is 1kHz;
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* Backlight pin is connected to TIM8 CR1.
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*/
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RCC->APB2ENR |= RCC_APB2ENR_TIM8EN;
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__DSB();
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TIM8->ARR = 255;
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TIM8->PSC = 654;
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TIM8->CNT = 0;
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TIM8->CR1 |= TIM_CR1_ARPE; /* LCD backlight is on PC6, TIM8-CH1 */
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TIM8->CCMR2 |= TIM_CCMR1_OC2M_2
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| TIM_CCMR1_OC2M_1
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| TIM_CCMR1_OC2PE;
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TIM8->CCER |= TIM_CCER_CC4E;
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TIM8->BDTR |= TIM_BDTR_MOE;
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TIM8->CCR1 = 0;
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TIM8->EGR = TIM_EGR_UG; /* Update registers */
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TIM8->CR1 |= TIM_CR1_CEN; /* Start timer */
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}
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void backlight_terminate()
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{
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/* Shut down backlight */
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gpio_setMode(LCD_BKLIGHT, OUTPUT);
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gpio_clearPin(LCD_BKLIGHT);
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/* Shut down timer */
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RCC->APB2ENR &= ~RCC_APB2ENR_TIM8EN;
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__DSB();
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}
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/*
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* This function is defined in display.h
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*/
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void display_setBacklightLevel(uint8_t level)
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{
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if(level > 100)
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level = 100;
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uint8_t pwmLevel = (2 * level) + (level * 55)/100; // Convert value to 0 - 255
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TIM8->CCR4 = pwmLevel;
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// Keyboard backlight does not have dimming, only on/off
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if(level > 0)
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gpioDev_set(KBD_BKLIGHT);
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else
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gpioDev_clear(KBD_BKLIGHT);
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}
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