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8 years, 4 months ago.
LPC1114 IRQ Problems on GPIO
I wrote two short test programs to try to get to the bottom of my on-going LPC interrupt problems. The way I understand it, all of the LPC1114 GPIO pins should be able to have IRQ's attached to them, bar the ones specically mentioned in the mbed LPC1114 pinout documentation. I am using dp13, dp14, dp26, dp27 and dp28. All are set for pull-up. On both versions, dp27 does NOT work - the input is not being pulled high and hovers around 100-400mV - the others are all sitting at 3.3V. My question is: Why are dp13 and dp27 not working correctly?
#include "mbed.h"
//this uses polling to check for PB going low
DigitalIn button1(dp13);
DigitalIn button2(dp14);
DigitalIn button3(dp28);
DigitalIn button4(dp27);
DigitalIn button5(dp26);
DigitalOut leds1(dp10);
DigitalOut leds2(dp11);
int main()
{
leds1 = 1;
leds2 = 1;
wait (3);
leds1 = 0; leds2 = 0;
button1.mode(PullUp);
button2.mode(PullUp);
button3.mode(PullUp);
button4.mode(PullUp);
button5.mode(PullUp);
LOOP:
if((button1 && button2 && button3 && button5) == 0) {
leds1 = 1;
wait_ms(250);
leds1 = 0;
}
goto LOOP;
}
(Note: Button 4 was note used in the LOOP part of the specific listing above for test purposes)
****************
Listed below is the INTERRUPT driven version.
1. dp14, dp26 and dp28 work. dp13 and dp27 (as mentioned above) do not respond to low going signals. 2. If I disable all IRQ's except dp13 and dp27, I can confirm they still do not work 3. If just dp13 and dp27 are disabled, dp14, dp26 and dp28 work
#include "mbed.h"
// this uses IRQ's to check for PB's going low
DigitalOut LEDS1(dp10);
//DigitalOut LEDS2(dp11);
InterruptIn PB1(dp13);
InterruptIn PB2(dp14);
InterruptIn PB3(dp26);
InterruptIn PB4(dp27);
InterruptIn PB5(dp28);
void PB1isr(void){
LEDS1 != LEDS1;
}
void PB2isr(void){
LEDS1 =! LEDS1;
}
void PB3isr(void){
LEDS1 =! LEDS1;
}
void PB4isr(void){
LEDS1 =! LEDS1;
}
void PB5isr(void){
LEDS1 =! LEDS1;
}
int main()
{
PB1.mode(PullUp);
PB2.mode(PullUp);
PB3.mode(PullUp);
PB4.mode(PullUp);
PB5.mode(PullUp);
PB1.fall(&PB1isr);
PB2.fall(&PB2isr);
PB3.fall(&PB3isr);
PB4.fall(&PB4isr);
PB5.fall(&PB5isr);
LEDS1 = 1;
wait (3);
LEDS1 = 0;
wait(3);
do {
wait_ms(250);
__WFI();
wait_ms(250);
} while(1);
}
Question relating to:
1 Answer
8 years, 4 months ago.
Dp27 is an easy one, it is an opendrain I2C pin: It does not have a pull up, so it is always low. What voltages do you measure on p13?
By the way, use <<code>> and <</code>> to make it better readable.
Erik, I put a 1k pull-up on p27 - it is now responding correctly (I read open drain as open drain for the output drive - I did not realize that it affected the input - good learning point).
Pin 13 has 3.3V and it goes to 0V when I hit the button, but it is not working - there is no response from the LED.
posted by 26 Nov 2015
I tested all the GPIO pins for IRQ - I have posted the results in the LPC1114 forum.
posted by Andrew R 28 Nov 2015