/* 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 3 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, see <http://www.gnu.org/licenses/>.
 *
 */
/* Copyright (c) 2016 King Kévin <kingkevin@cuvoodoo.info> */

/* standard libraries */
#include <stdint.h> // standard integer types
#include <stdio.h> // standard I/O facilities
#include <stdlib.h> // standard utilities
#include <unistd.h> // standard streams
#include <errno.h> // error number utilities

/* STM32 (including CM3) libraries */
#include <libopencm3/stm32/rcc.h> // real-time control clock library
#include <libopencm3/stm32/gpio.h> // general purpose input output library
#include <libopencm3/cm3/scb.h> // vector table definition
#include <libopencmsis/core_cm3.h> // Cortex M3 utilities

#include <libopencm3/stm32/timer.h>
#include <libopencm3/cm3/nvic.h>

/* own libraries */
#include "main.h" // board definitions
#include "usart.h" // USART utilities
#include "usb_cdcacm.h" // USB CDC ACM utilities
#include "vfd.h" // VFD driver

/* get the length of an array */
#define LENGTH(x) (sizeof(x) / sizeof((x)[0]))

/* default output (i.e. for printf) */
int _write(int file, char *ptr, int len)
{
	int i;

	if (file == STDOUT_FILENO || file == STDERR_FILENO) {
		for (i = 0; i < len; i++) {
			if (ptr[i] == '\n') { // add carrier return before line feed. this is recommended for most UART terminals
				usart_putchar_nonblocking('\r'); // a second line feed doesn't break the display
				cdcacm_putchar('\r'); // a second line feed doesn't break the display
			}
			usart_putchar_nonblocking(ptr[i]); // send byte over USART
			cdcacm_putchar(ptr[i]); // send byte over USB
		}
		return i;
	}
	errno = EIO;
	return -1;
}

static void gpio_setup(void)
{
	rcc_periph_clock_enable(LED_RCC); //enable clock for LED
	gpio_set_mode(LED_PORT, GPIO_MODE_OUTPUT_2_MHZ, GPIO_CNF_OUTPUT_PUSHPULL, LED_PIN); // set LED pin to 'output push-pull'	
}

static void timer_setup(void)
{
#define VFD_TIMER TIM2
#define VFD_TIMER_RCC RCC_TIM2
#define VFD_TIMER_IRQ NVIC_TIM2_IRQ

	rcc_periph_clock_enable(VFD_TIMER_RCC); // enable clock for timer block
	timer_reset(VFD_TIMER); // reset timer state
	timer_set_mode(VFD_TIMER, TIM_CR1_CKD_CK_INT, TIM_CR1_CMS_EDGE, TIM_CR1_DIR_UP); // set timer mode, use undivided timer clock,edge alignment (simple count), and count up
	timer_set_prescaler(VFD_TIMER, (SYSTEM_CLOCK_FREQ/(1<<16))-1); // set the prescaler so this 16 bits timer overflows at 1Hz
	//timer_set_period(0xffff/(VFD_DIGITS+VFD_MATRIX)/150); // set the refresh frequency
	timer_set_period(VFD_TIMER, 0xffff);
	timer_enable_irq(VFD_TIMER, TIM_DIER_CC1IE); // enable interrupt for timer
	nvic_enable_irq(VFD_TIMER_IRQ); // allow interrupt for timer
	timer_enable_counter(VFD_TIMER); // enable timer
}

void tim2_isr(void)
{
	if (timer_get_flag(VFD_TIMER, TIM_SR_UIF)) {
		timer_clear_flag(VFD_TIMER, TIM_SR_UIF);
		gpio_toggle(LED_PORT, LED_PIN);
	}
}

int main(void)
{	
	SCB_VTOR = (uint32_t) 0x08002000; // relocate vector table because of the bootloader
	rcc_clock_setup_in_hse_8mhz_out_72mhz(); // use 8 MHz high speed external clock to generate 72 MHz internal clock

	gpio_setup(); // setup main inputs/outputs
	usart_setup(); // setup USART (for printing)
	cdcacm_setup(); // setup USB CDC ACM (for printing)	
	vfd_setup(); // setup VFD
	timer_setup();
	
	setbuf(stdout, NULL); // set standard out buffer to NULL to immediately print	
	setbuf(stderr, NULL); // set standard error buffer to NULL to immediately print

	printf("welcome to the STM32F1 CuVoodoo display driver\n");


	vfd_on(); // switch on VFD
	vfd_test();
	vfd_shift();
	for (uint32_t i = 0; i < 0x800000; i++) {
		__asm__("nop");
	}
	vfd_clear();
	vfd_shift();
	vfd_digit(0,'0');
	vfd_shift();
	
	bool vfd_flag = false;
	for (uint8_t i=0; i<LENGTH(vfd_digits); i++) {
		vfd_digits[i] = '0'+i;
	}
	for (uint8_t i=0; i<LENGTH(vfd_matrixs); i++) {
		vfd_matrixs[i] = 'A'+i;
	}
	while (true) {
		while (usart_received) { // echo every received character
			printf("%c",usart_getchar()); // transmit receive character
			vfd_flag = true;
		}
		while (cdcacm_received) { // echo every received character
			printf("%c",cdcacm_getchar()); // transmit receive character
			vfd_flag = true;
		}
		while (vfd_flag) {
			vfd_flag = false;
			gpio_toggle(LED_PORT, LED_PIN); // toggle LED
			vfd_transmit();
		}
		__WFI(); // go to sleep
	}

	return 0;
}