main.c

/*
Blinky demo for GD32F3x0

Copyright (c) 2020, Bo Gao <7zlaser@gmail.com>

Redistribution and use in source and binary forms, with or without modification,
are permitted provided that the following conditions are met:

1. Redistributions of source code must retain the above copyright notice, this list of
   conditions and the following disclaimer.
2. Redistributions in binary form must reproduce the above copyright notice, this list
   of conditions and the following disclaimer in the documentation
   and/or other materials provided with the distribution.
3. Neither the name of the copyright holder nor the names of its contributors may be
   used to endorse or promote products derived from this software without specific
   prior written permission.

THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND ANY
EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
SHALL THE COPYRIGHT HOLDER BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THE
SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
*/

#include <stdio.h>
#include <stdlib.h>
#include <stdint.h>
#include "gd32f3x0.h"

volatile uint32_t tickcnt=0;

void delayms(uint32_t t)
{
	tickcnt=t*10;
	while(tickcnt);
}

void SysTick_Handler(void)
{
	if(tickcnt) tickcnt--;
}

uint8_t uart_getchar(void) {return 0;}

void uart_putchar(uint8_t c)
{
	usart_data_transmit(USART1, c);
	while(usart_flag_get(USART1, USART_FLAG_TBE)==RESET);
}

void main(void)
{
	//108MHz internal RC
	SystemInit();

	//100us SysTick
	SysTick_Config(SystemCoreClock/10000);
	NVIC_SetPriority(SysTick_IRQn, 0x00);

	//LED @ PB4
	rcu_periph_clock_enable(RCU_GPIOB);
	gpio_mode_set(GPIOB, GPIO_MODE_OUTPUT, GPIO_PUPD_NONE, GPIO_PIN_4);
	gpio_output_options_set(GPIOB, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, GPIO_PIN_4);
	gpio_bit_reset(GPIOB, GPIO_PIN_4);

	//UART1 @ PA14, PA15
	rcu_periph_clock_enable(RCU_GPIOA);
	gpio_af_set(GPIOA, GPIO_AF_1, GPIO_PIN_14);
	gpio_af_set(GPIOA, GPIO_AF_1, GPIO_PIN_15);
	gpio_mode_set(GPIOA, GPIO_MODE_AF, GPIO_PUPD_NONE, GPIO_PIN_14);
	gpio_mode_set(GPIOA, GPIO_MODE_AF, GPIO_PUPD_PULLUP, GPIO_PIN_15);
	gpio_output_options_set(GPIOA, GPIO_OTYPE_PP, GPIO_OSPEED_10MHZ, GPIO_PIN_14);
	rcu_periph_clock_enable(RCU_USART1);
	usart_deinit(USART1);
	usart_baudrate_set(USART1, 115200);
	usart_word_length_set(USART1, USART_WL_8BIT); //115200-8-n-1
	usart_parity_config(USART1, USART_PM_NONE);
	usart_stop_bit_set(USART1, USART_STB_1BIT);
	usart_parity_config(USART1, USART_PM_NONE);
	usart_receive_config(USART1, USART_RECEIVE_ENABLE);
	usart_transmit_config(USART1, USART_TRANSMIT_ENABLE);
	usart_enable(USART1);

	//Test float library
	float cnt=0.01;

	while(1)
	{
		//printf() tests file IO and malloc()
		//Floating point printf() is NOT enabled due to the size
		printf("Hello world %d.\r\n", (int)(cnt*100+0.5));
		cnt+=0.01;
		if(cnt>1.00) cnt=0.01;
		gpio_bit_write(GPIOB, GPIO_PIN_4, SET);
		delayms(500);
		gpio_bit_write(GPIOB, GPIO_PIN_4, RESET);
		delayms(500);
	}
}