/* *****************************************************************************
 * The MIT License
 *
 * Copyright (c) 2010 Perry Hung.
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 * THE SOFTWARE.
 * ****************************************************************************/

/**
 *  @file timers.h
 *
 *  @brief Timer prototypes and various definitions
 */

/* Note to self:
 * The timer clock frequencies are automatically fixed by hardware.
 * There are two cases:
 *     1.  if the APB prescaler is 1, the timer clock frequencies are
 *         set to the same frequency as that of the APB domain to which
 *         the timers are connected.
 *     2.  otherwise, they are set to twice (x2) the frequency of the
 *         APB domain to which the timers are connected.
 * See stm32 manual, 77/995
 *
 * hence, 72 mhz timers
 * */

/* Maple Timer channels:
 * Timer        Maple Pin               STM32 Pin     Type
 * TIM1_CH1     D6                      PA8           Advanced
 * TIM1_CH2     D7                      PA9           Advanced
 * TIM1_CH3     D8                      PA10          Advanced
 *
 * TIM2_CH1     D2                      PA0
 * TIM2_CH2     D3                      PA1
 * TIM2_CH3     D1                      PA2
 * TIM2_CH4     D0                      PA3
 *
 * TIM3_CH1     D12                     PA6
 * TIM3_CH2     D11                     PA7
 * TIM3_CH3     EXT7                    PB0
 * TIM3_CH4     EXT8                    PB1
 *
 * TIM4_CH1     EXT5                    PB6
 * TIM4_CH1     EXT9                    PB7
 * TIM4_CH1     EXT15                   PB8
 * TIM4_CH1     EXT4                    PB9
 *
 * Not supported:
 * TIM1_CH4    USBDM, not available     PA11          Advanced
 * TIM1_CH1_N  EXT12                    PB13
 * TIM1_CH2_N  EXT13                    PB14
 * TIM1_CH3_N  EXT14                    PB15
 * */

/* I don't like the Arduino API for dealing with pin modes.
 * How about...
 *
 * pinMode(digitalPin, PWM);
 * pwmWrite(digitalPin) */


#ifndef _TIMERS_H_
#define _TIMERS_H_

#ifdef __cplusplus
extern "C"{
#endif

typedef volatile uint32* TimerCCR;

#define TIMER1_BASE        0x40012C00
#define TIMER2_BASE        0x40000000
#define TIMER3_BASE        0x40000400
#define TIMER4_BASE        0x40000800

#define ARPE               BIT(7)                // Auto-reload preload enable
#define NOT_A_TIMER        0

#define TIMER1_CH1_CCR     (TimerCCR)(TIMER1_BASE + 0x34)
#define TIMER1_CH2_CCR     (TimerCCR)(TIMER1_BASE + 0x38)
#define TIMER1_CH3_CCR     (TimerCCR)(TIMER1_BASE + 0x3C)
#define TIMER1_CH4_CCR     (TimerCCR)(TIMER1_BASE + 0x40)

#define TIMER2_CH1_CCR     (TimerCCR)(TIMER2_BASE + 0x34)
#define TIMER2_CH2_CCR     (TimerCCR)(TIMER2_BASE + 0x38)
#define TIMER2_CH3_CCR     (TimerCCR)(TIMER2_BASE + 0x3C)
#define TIMER2_CH4_CCR     (TimerCCR)(TIMER2_BASE + 0x40)

#define TIMER3_CH1_CCR     (TimerCCR)(TIMER3_BASE + 0x34)
#define TIMER3_CH2_CCR     (TimerCCR)(TIMER3_BASE + 0x38)
#define TIMER3_CH3_CCR     (TimerCCR)(TIMER3_BASE + 0x3C)
#define TIMER3_CH4_CCR     (TimerCCR)(TIMER3_BASE + 0x40)

#define TIMER4_CH1_CCR     (TimerCCR)(TIMER4_BASE + 0x34)
#define TIMER4_CH2_CCR     (TimerCCR)(TIMER4_BASE + 0x38)
#define TIMER4_CH3_CCR     (TimerCCR)(TIMER4_BASE + 0x3C)
#define TIMER4_CH4_CCR     (TimerCCR)(TIMER4_BASE + 0x40)


/* Turn on timer with prescale as the divisor
 * void timer_init(uint32 timer, uint16 prescale)
 *      timer     ->  {1-4}
 *      prescale  ->  {1-65535}
 * */
void timer_init(uint8, uint16);
void timers_disable(void);
void timers_disable_channel(uint8, uint8);
void timers_set_prescaler(uint32 timer_num, uint16 prescale);
void timers_set_reload(uint32 timer_num, uint16 max_reload);

/* Turn on PWM with duty_cycle on the specified channel in timer.
 * This function takes in a pointer to the corresponding CCR
 * register for the pin cause it saves pwmWrite() a couple of
 * cycles.
 *
 * void timer_pwm(uint8 channel, uint8 duty_cycle);
 *      channel    -> {TIMERx_CHn_CCR}
 *      duty_cycle -> {0-65535}
 *
 * PRECONDITIONS:
 *      pin has been set to alternate function output
 *      timer has been initialized
 */
static inline void timer_pwm_write_ccr(TimerCCR CCR, uint16 duty_cycle) {
    *CCR = duty_cycle;
}


#ifdef __cplusplus
} // extern "C"
#endif


#endif