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stm32bringup/board.c

57 lines
1.5 KiB
C

/* board.c -- board mapping abstraction
** Copyright (c) 2020 Renaud Fivet
*/
#define SYSTICK ((volatile long *) 0xE000E010)
#define SYSTICK_CSR SYSTICK[ 0]
#define SYSTICK_RVR SYSTICK[ 1]
#define SYSTICK_CVR SYSTICK[ 2]
#define CAT( a, b) a##b
#define HEXA( a) CAT( 0x, a)
#define RCC ((volatile long *) 0x40021000)
#define RCC_AHBENR RCC[ 5]
#define RCC_AHBENR_IOP( h) (1 << (17 + HEXA( h) - 0xA))
#define GPIOA ((volatile long *) 0x48000000)
#define GPIOB ((volatile long *) 0x48000400)
#define GPIO( x) CAT( GPIO, x)
#define MODER 0
#define ODR 5
/* user LED ON when PA4 is high */
#define LED_IOP A
#define LED_PIN 4
#define LED_ON 1
void SysTick_Handler( void) {
#ifdef LED_ON
GPIO( LED_IOP)[ ODR] ^= 1 << LED_PIN ; /* Toggle User LED */
#endif
}
int init( void) {
/* By default SYSCLK == HSI [8MHZ] */
/* SYSTICK */
SYSTICK_RVR = 1000000 - 1 ; /* HBA / 8 */
SYSTICK_CVR = 0 ;
SYSTICK_CSR = 3 ; /* HBA / 8, Interrupt ON, Enable */
/* SysTick_Handler will execute every 1s from now on */
#ifdef LED_ON
/* User LED ON */
RCC_AHBENR |= RCC_AHBENR_IOP( LED_IOP) ; /* Enable IOPx periph */
GPIO( LED_IOP)[ MODER] |= 1 << (LED_PIN * 2) ; /* LED_IO Output [01],
** over default 00 */
/* OTYPER Push-Pull by default */
/* Pxn output default LOW at reset */
# if LED_ON
SysTick_Handler() ;
# endif
#endif
return 0 ;
}
/* end of board.c */