/* firmware for STM8S003-based dachboden badge
 * Copyright (C) 2019-2022 King Kévin <kingkevin@cuvoodoo.info>
 * SPDX-License-Identifier: GPL-3.0-or-later
 */
#include <stdint.h>
#include <stdbool.h>
#include <stdlib.h>

#include "stm8s.h"
#include "main.h"

// enable UART debug
#define DEBUG 1

// pinout
// on-board LED (sink on)
#define LED_ONBOARD_PIN PB5
#define LED_ONBOARD_PORT GPIO_PB
// pin to power IR demodulator (source on)
#define IRM_ON_PIN PA3
#define IRM_ON_PORT GPIO_PA
// IR demodulator output pin
#define IRM_OUT_PIN PC7 // TIM1_CH2
#define IRM_OUT_PORT GPIO_PC
// RGB LED pins (sink on)
#define LED_RED_PIN PD3 // TIM2_CH2
#define LED_RED_PORT GPIO_PD
#define LED_GREEN_PIN PD2 // TIM2_CH3
#define LED_GREEN_PORT GPIO_PD
#define LED_BLUE_PIN PC5 // TIM2_CH1
#define LED_BLUE_PORT GPIO_PC
// IR LED pin (source on)
#define LED_IR_PIN PC4 // TIM1_CH4
#define LED_IR_PORT GPIO_PC
// UV LED pin (source on)
#define LED_UV_PIN PC3 // TIM1_CH3
#define LED_UV_PORT GPIO_PC
// vibration sensor input (high on vibration)
#define SHAKE_PIN PA2
#define SHAKE_PORT GPIO_PA
#define SHAKE_IRQ IRQ_EXTI0 // port A

// number of vibrations registered
static volatile uint16_t shake_count = 0;
// number of time counts (+1 @ 488 Hz)
static volatile uint32_t time_count = 0;

// blocking wait (in 10 us steps, up to UINT32_MAX / 10)
static void wait_10us(uint32_t us10)
{
	us10 = ((us10 / (1 << CLK->CKDIVR.fields.HSIDIV)) * 1000) / 206; // calibrated for 1 ms
	while (us10--); // burn energy
}

void putc(char c)
{
	(void)c;
	IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
#if DEBUG
	while (!UART1->SR.fields.TXE); // wait until TX buffer is empty
	UART1->DR.reg = c; // put character in buffer to be transmitted
	// don't wait until the transmission is complete
#endif
}

void puts(const char* s)
{
	if (NULL == s) {
		return;
	}
	while (*s) {
		putc(*s++);
	}
}

void putn(uint8_t n)
{
	n &= 0x0f; // ensure it's a nibble
	if (n < 0xa) {
		n += '0';
	} else {
		n = 'a' + (n - 0x0a);
	}
	putc(n);
}

void puth(uint8_t h)
{
	putn(h >> 4);
	putn(h & 0x0f);
}

void main(void)
{
	sim(); // disable interrupts (while we reconfigure them)

	CLK->CKDIVR.fields.HSIDIV = CLK_CKDIVR_HSIDIV_DIV0; // don't divide internal 16 MHz clock
	CLK->CKDIVR.fields.CPUDIV = CLK_CKDIVR_CPUDIV_DIV0; // don't divide CPU frequency to 16 MHz
	while (!CLK->ICKR.fields.HSIRDY); // wait for internal oscillator to be ready

	// TODO only enable clock for peripherals used (PCG)

	// configure LED pin
	LED_ONBOARD_PORT->ODR.reg |= LED_ONBOARD_PIN; // switch LED off
	LED_ONBOARD_PORT->CR1.reg &= ~LED_ONBOARD_PIN; // use as open-drain
	LED_ONBOARD_PORT->DDR.reg |= LED_ONBOARD_PIN; // switch pin to output

	// configure option bytes
	// disable DATA (e.g. option byte) write protection
	if (0 == (FLASH_IAPSR & FLASH_IAPSR_DUL)) {
		FLASH_DUKR = FLASH_DUKR_KEY1;
		FLASH_DUKR = FLASH_DUKR_KEY2;
	}
	FLASH_CR2 |= FLASH_CR2_OPT; // set option bytes programming
	FLASH_NCR2 &= ~FLASH_NCR2_NOPT; // set option bytes programming

	OPT->OPT2.fields.AFR0 = 1; // remap TIM2_CH1 to PC5, TIM1_CH1 to C6, and TIM1_CH2 to C7
	OPT->NOPT2.fields.NAFR0 = 0; // set complementary option byte
	OPT->OPT2.fields.AFR1 = 1; // remap TIM2_CH3 to PD2
	OPT->NOPT2.fields.NAFR1 = 0; // set complementary option byte

	while (!(FLASH_IAPSR & FLASH_IAPSR_EOP)); // wait for write to complete
	FLASH_IAPSR &= ~FLASH_IAPSR_DUL; // re-enable write protection

	// configure UART for debug output
	UART1->CR1.fields.M = 0; // 8 data bits
	UART1->CR3.fields.STOP = 0; // 1 stop bit
	UART1->BRR2.reg = 0x0B; // set baud rate to 115200 (at 16 MHz)
	UART1->BRR1.reg = 0x08; // set baud rate to 115200 (at 16 MHz)
	UART1->CR2.fields.TEN = 1; // enable TX

	// configure IR demodulator pin
	IRM_ON_PORT->ODR.reg &= ~IRM_ON_PIN; // switch IR demodulator off
	IRM_ON_PORT->ODR.reg |= IRM_ON_PIN; // switch IR demodulator on
	IRM_ON_PORT->CR1.reg |= IRM_ON_PIN; // use as push-pull
	IRM_ON_PORT->DDR.reg |= IRM_ON_PIN; // switch pin to output

	// configure RGB LED
	LED_RED_PORT->ODR.reg |= LED_RED_PIN; // switch LED off
	LED_RED_PORT->CR1.reg &= ~LED_RED_PIN; // use as open-drain
	LED_RED_PORT->DDR.reg |= LED_RED_PIN; // use pin to output
	LED_GREEN_PORT->ODR.reg |= LED_GREEN_PIN; // switch LED off
	LED_GREEN_PORT->CR1.reg &= ~LED_GREEN_PIN; // use as open-drain
	LED_GREEN_PORT->DDR.reg |= LED_GREEN_PIN; // use pin to output
	LED_BLUE_PORT->ODR.reg |= LED_BLUE_PIN; // switch LED off
	LED_BLUE_PORT->CR1.reg &= ~LED_BLUE_PIN; // use as open-drain
	LED_BLUE_PORT->DDR.reg |= LED_BLUE_PIN; // use pin to output

/*
	// configure IR LED
	LED_IR_PORT->ODR.reg &= ~LED_IR_PIN; // switch LED off
	LED_IR_PORT->CR1.reg |= LED_IR_PIN; // use as push-pull
	LED_IR_PORT->DDR.reg |= LED_IR_PIN; // use pin to output
*/

	// configure UV LED
	LED_UV_PORT->ODR.reg &= ~LED_UV_PIN; // switch LED off
	LED_UV_PORT->CR1.reg |= LED_UV_PIN; // use as push-pull
	LED_UV_PORT->DDR.reg |= LED_UV_PIN; // use pin to output

	// configure vibration sensor input
	SHAKE_PORT->CR1.reg &= ~SHAKE_PIN; // leave floating (pulled down externally)
	SHAKE_PORT->DDR.reg &= ~SHAKE_PIN; // set as input
	SHAKE_PORT->CR2.reg |= SHAKE_PIN; // enable external input
	EXTI->CR1.fields.PAIS = EXTI_RISING_EDGE; // interrupt when vibration is detected
	shake_count = 0; // reset counter

	// use timer 4 (8-bit) as timeout counter
	TIM4->PSCR.fields.PSC = 7; // make it as slow as possible 16E6 / 2**7 = 125 kHz, / 256 = 488 Hz
	TIM4->CNTR.fields.CNT = 0; // reset counter
	TIM4->IER.fields.UIE = 1; // enable interrupt
	time_count = 0; // reset time counter
	TIM4->CR1.fields.URS = 1; // only update on overflow
	TIM4->CR1.fields.CEN = 1; // enable counter

	// configure timer to modulate IR LEDs at 38 kHz
	TIM1->PSCRH.reg = 0; // set prescaler to get most precise 38 kHz
	TIM1->PSCRL.reg = 0; // 16E6/(0+1)/65536 = down to 244 Hz
	#define TIM1_PERIOD 421U // 16E6/(0+1)/38000
	TIM1->ARRH.reg = (TIM1_PERIOD >> 8); // set auto-reload register for 38 kHz period
	TIM1->ARRL.reg = (TIM1_PERIOD & 0xff); // 16E6/(0+1)/38000
	TIM1->CCR4H.reg = (TIM1_PERIOD / 3) >> 8; // set duty cycle to 33%
	TIM1->CCR4L.reg = (TIM1_PERIOD / 3 ) & 0xff; // set duty cycle to 33%
	TIM1->CCMR4.output_fields.OC4M = 6; // set PWM1 mode
	TIM1->CCMR4.output_fields.CC4S = 0; // use channel as output
	TIM1->CCER2.fields.CC4E = 1; // enable channel output
	TIM1->BKR.fields.MOE = 1; // enable outputs
	TIM1->EGR.fields.UG = 1; // transfer all registers
	TIM1->CR1.fields.CEN = 1; // enable counter to start PWM

/* don't use the AWU, else it will cause an active-halt instead of halt, using more power
	// configure auto-wakeup (AWU) to be able to refresh the watchdog
	// 128 kHz LSI used by default in option bytes CKAWUSEL
	// we skip measuring the LS clock frequency since there is no need to be precise
	AWU->TBR.fields.AWUTB = 10; // interval range: 128-256 ms
	AWU->APR.fields.APR = 0x3e; // set time to 256 ms
	AWU->CSR.fields.AWUEN = 1; // enable AWU (start only when entering wait or active halt mode)
*/

/* don't use IWDG since it wakes up from HALT mode and uses (a little) power
   use WWDG instead
	// configure independent watchdog (very loose, just it case the firmware hangs)
	IWDG->KR.fields.KEY = IWDG_KR_KEY_REFRESH; // reset watchdog
	IWDG->KR.fields.KEY = IWDG_KR_KEY_ENABLE; // start watchdog
	IWDG->KR.fields.KEY = IWDG_KR_KEY_ACCESS; // allows changing the prescale
	IWDG->PR.fields.PR = IWDG_PR_DIV256; // set prescale to longest time (1.02s)
	IWDG->KR.fields.KEY = IWDG_KR_KEY_REFRESH; // reset watchdog
*/

	rim(); // re-enable interrupts
	LED_ONBOARD_PORT->ODR.reg &= ~LED_ONBOARD_PIN; // switch LED on to indicate we are ready
	bool action = false; // if an action has been performed
	puts("ready\r\n");
	while (true) {
		putc('.');
		IWDG_KR = IWDG_KR_KEY_REFRESH; // reset watchdog
		if (shake_count) {
			puts("vibrations: ");
			puth(shake_count);
			puts("\r\n");
			shake_count = 0; // reset count
		}
		if (time_count > 488 * 10) {
			puts("10s\r\n");
			time_count = 0; // reset counter
			halt();
		}
		if (action) { // something has been performed, check if other flags have been set meanwhile
			action = false; // clear flag
		} else { // nothing down
			wfi(); // go to sleep (wait for any interrupt, including periodic AWU)
		}
	}
}

// auto wakeup
void awu(void) __interrupt(IRQ_AWU)
{
	volatile uint8_t awuf = AWU_CSR; // clear interrupt flag by reading it (reading is required, and volatile prevents compiler optimization)
	// let the main loop kick the dog
}

// vibration sensor input
void shake_isr(void) __interrupt(SHAKE_IRQ)
{
	shake_count++; // register vibration
}

// time counter
void time_isr(void) __interrupt(IRQ_TIM4)
{
	TIM4->SR.fields.UIF = 0; // clear flag
	time_count++; // remember overflow to count time
}