#include "fw_hal.h" static uint8_t counter = 0; INTERRUPT(Timer2_Routine, EXTI_VectTimer2) { counter++; if (counter == 5) { counter = 0; UART1_TxString("hello\r\n"); } } void main(void) { SYS_Init(); // UART1 configuration: baud 115200 with Timer1, 1T mode, no interrupt UART1_ConfigMode1Dyn8bitUart(UART1_BaudSource_Timer1, HAL_State_ON, 115200, HAL_State_OFF); EXTI_Global_SetIntState(HAL_State_ON); // 1T mode, prescaler:255+1, frequency: 5, interrupt: ON TIM_Timer2_Config(HAL_State_ON, 0xFF, 5, HAL_State_ON); TIM_Timer2_SetRunState(HAL_State_ON); while(1); }