I have a new project involving timer generated pulses, with a pulse interval between 20 uS and 1mS. The timers are turned on with an initial compare value, and the timer ISR, in addition to generating the pulse, loads a new compare value if required.
This sample code with two timers shows my problem. The pulses are generated, but instead of the pulse interval being determined by the compare value of at least 100uS, the interval is approximate 1uS.
It looks like the interrupt is never cleared, putting the ISR into an endless loop.
So what am I missing?
Little aside: in March I was told that all the mbed timer stuff uses timer 3, but I saw something recently saying that it uses timer 0. Has a change been made?
#include “mbed.h”

void SetupTimer0(void);
void Timer0_IRQHandler(void);
void SetupTimer1(void);
void Timer1_IRQHandler(void);

DigitalOut myled(LED1);
DigitalOut myled2(LED2);
DigitalOut X_STEP_PIN(p15);
DigitalOut Y_STEP_PIN(p17);

int main() {
SetupTimer0();
SetupTimer1();
while(1) {
// myled2 = 1;
// wait(0.2);
// myled2 = 0;
// wait(0.2);
}
}

void SetupTimer1(void)
{
LPC_SC->PCONP |= 1 << 2; // Power on Timer`
LPC_TIM1->TCR = 0×2; // Reset and set to timer mode
LPC_TIM1->CTCR = 0×0;
LPC_TIM1->PR = 0; // No prescale
LPC_TIM1->MR0 = 2398; // Match count for 100mS
LPC_TIM1->MCR = 3; // Interrupt and Reset on Match
LPC_TIM1->TCR = 1; // Enable Timer

// Enable the ISR vector
NVIC_SetVector (TIMER1_IRQn, (uint32_t)&Timer1_IRQHandler);
NVIC_EnableIRQ(TIMER1_IRQn);
}

void Timer1_IRQHandler(void)
{
X_STEP_PIN = 1;
LPC_TIM1->MR0 = 23980; // Match count for Step Interval
myled2 = !myled2;
X_STEP_PIN = 0;
}
void SetupTimer0(void)
{
LPC_SC-> PCONP |= 1 << 1; // Power on Timer0
LPC_TIM0->TCR = 0×2; // Reset and set to timer mode
LPC_TIM0->CTCR = 0×0;
LPC_TIM0->PR = 0; // No prescale
LPC_TIM0->MR0 = 2398; // Match count for 100mS
LPC_TIM0->MCR = 3; // Interrupt, Stop, and Reset on match
LPC_TIM0->TCR = 1; // Enable Timer0
// Enable the ISR vector
NVIC_SetVector (TIMER0_IRQn, (uint32_t)&Timer0_IRQHandler);
NVIC_EnableIRQ(TIMER0_IRQn);
}

void Timer0_IRQHandler(void)
{
Y_STEP_PIN = 1;
LPC_TIM0->MR0 = 239800; // Match count for Step Interval
myled = !myled;
Y_STEP_PIN = 0;
}