Posted on October 13, 2014 at 18:27Hi everyone.
I need some explain why this code generating not 1KHz TIM2 interrupt.
I have no idea why generating 2KHz in APB1 clock(30MHz) & PPRE1(0b101) & CKD(0b00).
#include ''stm32f2xx.h''
void
TIM2_IRQHandler
()
{
TIM2
->
SR
&=~
1
;
GPIOA
->
ODR
^=
0x00000001
;
//PA0 Toggle
}
int
main
()
{
RCC
->
AHB1ENR
|=
0x00000001
;
//PA0 Clock EN
RCC
->
APB1ENR
|=
0x00000001
;
//TIM2 Clock EN
GPIOA
->
MODER
|=
0x00000001
;
//PA0 Output
//
TIM2
->
PSC
=
10
-
1
;
//Prescaler //APB1clk/Presclr/fOUT = ARR <=0xFFFF //PPRE1 101: AHB/4=30MHz
TIM2
->
ARR
=
3000
-
1
;
//Period
TIM2
->
EGR
|=
0x0001
;
//Update generation
TIM2
->
DIER
|=
0x0001
;
//Update interrupt EN
TIM2
->
CR1
|=
0x0001
;
//CKD : 0 //Up Counter //Counter EN
//
SCB
->
AIRCR
|=
0x00000300
;
//Group 7:4 //Sub None
NVIC
->
IP[
28
]
|=
0xF0
;
//TIM2 Global Interrupt : Position [28] //Priority group 15
NVIC
->
ISER[
0
]
|=
0x10000000
;
//TIM2 Interrupt SET //[28]>>0x05==[0] //1<<(IRQ_CH&0x1F)
while
(
1
){}
}
