You cannot select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
83 lines
2.1 KiB
C
83 lines
2.1 KiB
C
#include "stm32l476xx.h"
|
|
|
|
#define STK_CTRL *((uint32_t *)0xE000E010)
|
|
#define STK_LOAD *((uint32_t *)0xE000E014)
|
|
#define STK_VAL *((uint32_t *)0xE000E018)
|
|
#define STK_CALIB *((uint32_t *)0xE000E01C)
|
|
|
|
extern void delay(uint32_t count);
|
|
|
|
/**
|
|
* Accomplishments:
|
|
* - GPIO in/out
|
|
* - got to 40MHz clock
|
|
*/
|
|
|
|
void pulse(uint8_t byte);
|
|
|
|
int main(void)
|
|
{
|
|
// prepare flash latency for 40MHz operation
|
|
FLASH->ACR &= ~(FLASH_ACR_LATENCY);
|
|
FLASH->ACR |= FLASH_ACR_LATENCY_2WS;
|
|
|
|
// turn on HSI
|
|
RCC->CR |= RCC_CR_HSION;
|
|
while ((RCC->CR & RCC_CR_HSIRDY) != RCC_CR_HSIRDY);
|
|
|
|
// get PLLR to 80MHz (max)
|
|
// VCO = C * (N/M) -> 16 * (10/1) = 160
|
|
// SCLK = VCO / R = 160 / 4 = 40 MHz
|
|
RCC->PLLCFGR &= ~(RCC_PLLCFGR_PLLSRC); // source HSI, 16MHz
|
|
RCC->PLLCFGR |= RCC_PLLCFGR_PLLSRC_HSI;
|
|
RCC->PLLCFGR &= ~(RCC_PLLCFGR_PLLN | RCC_PLLCFGR_PLLM);
|
|
RCC->PLLCFGR |= 10 << RCC_PLLCFGR_PLLN_Pos;
|
|
RCC->PLLCFGR &= ~(RCC_PLLCFGR_PLLR); // /4
|
|
RCC->PLLCFGR |= 1 << RCC_PLLCFGR_PLLR_Pos;
|
|
RCC->PLLCFGR |= RCC_PLLCFGR_PLLREN; // PLLR on
|
|
|
|
// start PLL
|
|
RCC->CR |= RCC_CR_PLLON;
|
|
while ((RCC->CR & RCC_CR_PLLRDY) != RCC_CR_PLLRDY);
|
|
|
|
// set system clock to PLL
|
|
RCC->CFGR &= ~(RCC_CFGR_SW);
|
|
RCC->CFGR |= RCC_CFGR_SW_PLL;
|
|
while ((RCC->CFGR & RCC_CFGR_SWS_PLL) != RCC_CFGR_SWS_PLL);
|
|
|
|
// SysTick setup? Assume 4MHz reset clock
|
|
STK_LOAD = 40000;
|
|
STK_CTRL |= 0x07; // AHB, inten, enable
|
|
|
|
RCC->AHB2ENR |= RCC_AHB2ENR_GPIOAEN; // A clk enable
|
|
GPIOA->MODER &= ~(GPIO_MODER_MODE5 | GPIO_MODER_MODE0); // A5 -> output, A0 input
|
|
GPIOA->MODER |= GPIO_MODER_MODE5_0;
|
|
GPIOA->PUPDR &= ~(GPIO_PUPDR_PUPD5 | GPIO_PUPDR_PUPD0);
|
|
GPIOA->PUPDR |= GPIO_PUPDR_PUPD5_0 | GPIO_PUPDR_PUPD0_1; // pd for button
|
|
|
|
pulse(*((uint8_t *)0x08080000)); // 0b00100101
|
|
|
|
while (1);/* {
|
|
delay(500);
|
|
//if (GPIOA->IDR & 0x01)
|
|
GPIOA->BSRR |= 1 << 5;
|
|
delay(500);
|
|
//else
|
|
GPIOA->BRR |= 1 << 5;
|
|
}*/
|
|
}
|
|
|
|
void _exit(int code)
|
|
{ for (;;); }
|
|
|
|
void pulse(uint8_t byte)
|
|
{
|
|
int8_t i = 7;
|
|
do {
|
|
GPIOA->BSRR |= 1 << 5;
|
|
delay((byte & (1 << i)) ? 400 : 100);
|
|
GPIOA->BRR |= 1 << 5;
|
|
delay((byte & (1 << i)) ? 100 : 400);
|
|
} while (--i >= 0);
|
|
}
|