mirror of
https://github.com/rfivet/stm32bringup.git
synced 2024-12-18 06:46:23 -05:00
57 lines
1.5 KiB
C
57 lines
1.5 KiB
C
/* board.c -- board mapping abstraction
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** Copyright (c) 2020 Renaud Fivet
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*/
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#define SYSTICK ((volatile long *) 0xE000E010)
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#define SYSTICK_CSR SYSTICK[ 0]
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#define SYSTICK_RVR SYSTICK[ 1]
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#define SYSTICK_CVR SYSTICK[ 2]
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#define CAT( a, b) a##b
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#define HEXA( a) CAT( 0x, a)
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#define RCC ((volatile long *) 0x40021000)
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#define RCC_AHBENR RCC[ 5]
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#define RCC_AHBENR_IOP( h) (1 << (17 + HEXA( h) - 0xA))
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#define GPIOA ((volatile long *) 0x48000000)
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#define GPIOB ((volatile long *) 0x48000400)
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#define GPIO( x) CAT( GPIO, x)
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#define MODER 0
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#define ODR 5
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/* user LED ON when PA4 is high */
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#define LED_IOP A
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#define LED_PIN 4
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#define LED_ON 1
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void SysTick_Handler( void) {
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#ifdef LED_ON
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GPIO( LED_IOP)[ ODR] ^= 1 << LED_PIN ; /* Toggle User LED */
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#endif
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}
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int init( void) {
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/* By default SYSCLK == HSI [8MHZ] */
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/* SYSTICK */
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SYSTICK_RVR = 1000000 - 1 ; /* HBA / 8 */
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SYSTICK_CVR = 0 ;
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SYSTICK_CSR = 3 ; /* HBA / 8, Interrupt ON, Enable */
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/* SysTick_Handler will execute every 1s from now on */
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#ifdef LED_ON
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/* User LED ON */
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RCC_AHBENR |= RCC_AHBENR_IOP( LED_IOP) ; /* Enable IOPx periph */
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GPIO( LED_IOP)[ MODER] |= 1 << (LED_PIN * 2) ; /* LED_IO Output [01],
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** over default 00 */
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/* OTYPER Push-Pull by default */
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/* Pxn output default LOW at reset */
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# if LED_ON
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SysTick_Handler() ;
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# endif
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#endif
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return 0 ;
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}
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/* end of board.c */
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