STM8s Timer 2 usage

Introduction: I recently started using the stm8s103k microcontroller, and today I will record the use of its timer 2. First of all, it needs to be explained that the stm8s manual says that TIM2 16-bit counts up, which is wrong.

The stm8s timing is easy to use. First, set the clock frequency of the timer. Once the clock period T of the timer is known, the timing time Tn is determined, that is, Tn = T * ARR (automatically load data).

The procedure is as follows:

1. MCU clock setting:

//fmaster=fcpu=2MHz

CLK_ECKR=0x00;

CLK_ICKR=0x01;

CLK_CMSR=0xe1;

CLK_SWR=0xe1;

CLK_CKDIVR=0x18;

2. Timer TIM2 initialization

//Timer 2 initialization fmaster/frequency division = 2M/2 = 1M, count once in 1us, interrupt once in 50us

void TIM2_Init(void)

{

_asm("sim"); //sim is to disable interrupts

TIM2_IER = 0x00; //Disable interrupt

TIM2_EGR = 0x01; //Allow update flag to be generated

TIM2_PSCR =0x01; //Set clock division 2M/2=1MHz---1us

TIM2_ARRH = 0x00; //0x32=50; Cycle = 50 times, reset timer 2 every 50us

TIM2_ARRL = 0x32; //ARR automatically loads value, decrements by 1 every 1us

TIM2_CNTRH=0x00; //initial value

TIM2_CNTRL=0x00;

TIM2_CR1 |= 0x81; //Start the timer

TIM2_IER |= 0x01; //Enable interrupt

_asm("rim"); //rim enables interrupt

}

3. Interrupt execution of program

@far @interrupt void TIM2_UPD_IRQHandler(void)

{

TIM2_SR1 &=~(0x01); //=0x0e; // Clear interrupt flag

PC_ODR=~PC_ODR; //You need to configure pc and pb as output ports first

PB_ODR=~PB_ODR;

}

4. Modify the interrupt vector table

Open the stm8_interrupt_vector.c file and add the following content:

extern @far @interrupt void TIM2_UPD_IRQHandler(void);

Modify the following line:

{0x82, NonHandledInterrupt},

for:

{0x82,(interrupt_handler_t)TIM2_UPD_IRQHandler},

That's it, you can try it.

During my operation, I encountered a very annoying problem, that is, the downloader often does not work, error number 30006, 30003.

In both cases, first confirm whether your stlink wiring is correct, and then measure the voltage of the 4 download pins. The correct voltage is: 5V, Gnd, NRST-5V, SWIM-0v (roughly like this). If there is no problem above, it may be that the downloader and the computer are not connected properly. You need to reconnect and confirm the software (Target-setting).