Lpc2000

Hello All!
	I'm trying to write a simple interrupt routine for a external interrupt 
source (EINT0) for a LPC2106. As there's no selection between level or 
edge-triggered interrupts, I want to to wait until there's a logic 1 on the 
EINTx pin to clear the intrrupt on the VIC to not count a long strobe as 
several different interrupts. This goes along with the LPC2106 user's manual, 
as on page 40 it says that to clear a pending intrerrupt on EINTx I have to 
wait until there's a high level on the pin, so I REALLY want to wait until a 
logic 1 is present. But how do I do that?
	I already tried a code like this in my interrupt handler:

(defines based on freeRTOS)

	while( (GPIO0_IOPIN & (0x01<<16)) == 0 );
	SCB_EXTINT |= 0x01;
	VICVectAddr = serCLEAR_VIC_INTERRUPT;

	If I remove the while() loop; I get several interrupts, as expected. But if I 
leave the loop, after the first strobe on the pin, the processor gets stuck. 
Can I use the IOPIN register to read the current logic level on the pin? I 
think so, by reading the register description on page 81 of the UM.

Thanks a lot

-- 

Leonardo Pereira Santos
Engenheiro de Projetos

Easy - 

Use a LPC23xx series chip!

I don't know why they did level interrupts on the LPC21xx series (easier to impliment?). I have never used a level interrupt in a micro controller. 

You could use a D flipflop (Q Bar output) and a port line to reset it. The line will be high again before you reenable the intterupt. Thats what I was planning in a previous project. Fortunalty it has been delayed until now and I am planning on using a LPC 23xx solution and an edge triggered interrupt.  

Owen Mooney

Hello All!
	I'm trying to write a simple interrupt routine for a external interrupt 
source (EINT0) for a LPC2106. As there's no selection between level or 
edge-triggered interrupts, I want to to wait until there's a logic 1 on the 
EINTx pin to clear the intrrupt on the VIC to not count a long strobe as 
several different interrupts. This goes along with the LPC2106 user's manual, 
as on page 40 it says that to clear a pending intrerrupt on EINTx I have to 
wait until there's a high level on the pin, so I REALLY want to wait until a 
logic 1 is present. But how do I do that?
	I already tried a code like this in my interrupt handler:

Hi


You can not read the port via GPIO when the port is defined as
External Int. You hav to try clearing the bit until it is accepted.

I do this
 	while( SCB_EXTINT & 0x01 )
             {
 	       SCB_EXTINT = 0x01;
 	      }
       VICVectAddr = serCLEAR_VIC_INTERRUPT;


best regards

John Noergaard



--- In lpc2000@yahoogroups.com, Leonardo Santos <lsantos@p...> wrote:
> Hello All!
> 	I'm trying to write a simple interrupt routine for a external
interrupt 
> source (EINT0) for a LPC2106. As there's no selection between level or 
> edge-triggered interrupts, I want to to wait until there's a logic 1
on the 
> EINTx pin to clear the intrrupt on the VIC to not count a long
strobe as 
> several different interrupts. This goes along with the LPC2106
user's manual, 
> as on page 40 it says that to clear a pending intrerrupt on EINTx I
have to 
> wait until there's a high level on the pin, so I REALLY want to wait
until a 
> logic 1 is present. But how do I do that?
> 	I already tried a code like this in my interrupt handler:
> 
> (defines based on freeRTOS)
> 
> 	while( (GPIO0_IOPIN & (0x01<<16)) == 0 );
> 	SCB_EXTINT |= 0x01;
> 	VICVectAddr = serCLEAR_VIC_INTERRUPT;
> 
> 	If I remove the while() loop; I get several interrupts, as
expected. But if I 
> leave the loop, after the first strobe on the pin, the processor
gets stuck. 
> Can I use the IOPIN register to read the current logic level on the
pin? I 

> think so, by reading the register description on page 81 of the UM.
> 
> Thanks a lot
> 
> -- 
> 
> Leonardo Pereira Santos
> Engenheiro de Projetos