Question
How to use GPIO external interrupts
Posted on June 24, 2011 at 07:31
Hi,
Port-c pc6 is connected to a 50 Hz square wave signal, the problem is the variable cCounter did not increment in the port_c_isr, so the PC4 pin did not toggle, please advise about the solution. Thanks ======================================================== #include <iostm8s903.h> unsigned char cCounter; void main(void) { CLK_ICKCR = 0x01; // high speed internal osc enable CLK_ECKCR = 0x00; // high speed xtal osc disable CLK_SWR = 0xE1; // select high speed internal osc as master clock CLK_CKDIVR = 0x10; // master clk divide / 4, cpu clk div / 1 PC_ODR = 0x9E; PC_DDR = 0x9E; PC_CR1 = 0xFF; PC_CR2 = 0x40; // pc6 interrupt enable EXTI_CR1 = 0x20; // port-c interrupt falling edge only // global interrupt enable _asm(''rim''); while (1) { while (cCounter < 25); PC_ODR |= 0x10; // set PC4 pin cCounter = 0; while (cCounter < 25); PC_ODR &= ~0x10; // clear PC4 pin cCounter = 0; } } @far @interrupt void port_c_isr(void) { cCounter++; } ===================================== stm8_interrupt_vector.c file contents ===================================== /* BASIC INTERRUPT VECTOR TABLE FOR STM8 devices * Copyright (c) 2007 STMicroelectronics */ typedef void @far (*interrupt_handler_t)(void); struct interrupt_vector { unsigned char interrupt_instruction; interrupt_handler_t interrupt_handler; }; @far @interrupt void NonHandledInterrupt(void) { // in order to detect unexpected events during development, // it is recommended to set a breakpoint on the following instruction return; } extern @far @interrupt void port_c_isr(void); extern void _stext(); /* startup routine */ struct interrupt_vector const _vectab[] = { {0x82, (interrupt_handler_t)_stext}, /* reset */ {0x82, NonHandledInterrupt}, /* trap */ {0x82, NonHandledInterrupt}, /* irq0 */ {0x82, NonHandledInterrupt}, /* irq1 */ {0x82, NonHandledInterrupt}, /* irq2 */ {0x82, NonHandledInterrupt}, /* irq3 */ {0x82, NonHandledInterrupt}, /* irq4 */ {0x82, port_c_isr}, /* irq5 port-c exti */ {0x82, NonHandledInterrupt}, /* irq6 */ {0x82, NonHandledInterrupt}, /* irq7 */ {0x82, NonHandledInterrupt}, /* irq8 */ {0x82, NonHandledInterrupt}, /* irq9 */ {0x82, NonHandledInterrupt}, /* irq10 */ {0x82, NonHandledInterrupt}, /* irq11 */ {0x82, NonHandledInterrupt}, /* irq12 */ {0x82, NonHandledInterrupt}, /* irq13 */ {0x82, NonHandledInterrupt}, /* irq14 */ {0x82, NonHandledInterrupt}, /* irq15 */ {0x82, NonHandledInterrupt}, /* irq16 */ {0x82, NonHandledInterrupt}, /* irq17 */ {0x82, NonHandledInterrupt}, /* irq18 */ {0x82, NonHandledInterrupt}, /* irq19 */ {0x82, NonHandledInterrupt}, /* irq20 */ {0x82, NonHandledInterrupt}, /* irq21 */ {0x82, NonHandledInterrupt}, /* irq22 */ {0x82, NonHandledInterrupt}, /* irq23 */ {0x82, NonHandledInterrupt}, /* irq24 */ {0x82, NonHandledInterrupt}, /* irq25 */ {0x82, NonHandledInterrupt}, /* irq26 */ {0x82, NonHandledInterrupt}, /* irq27 */ {0x82, NonHandledInterrupt}, /* irq28 */ {0x82, NonHandledInterrupt}, /* irq29 */ };