Most dspic can use the MCLR pin as a normal I/O pin. Check that you have
that pin as I/O instead of normal reset.

Check also the voltage at the MCLR pin when you are pressing the button. It
has to be near 0V, check datasheet for value range.
 El dia 07/04/2015 11:23, "IVP" <joecolquitt@clear.net.nz> va escriure:

> Hi all,
>
> is there a particular procedure for causing a dsPIC reset with
> a switch or IC ? I've got a dsPIC circuit with a tact switch on
> /MCLR that doesn't seem to do a proper hardware reset. At
> some point I'd like to add a reset from another device, and a
> tact switch seemed a quick test
>
> /MCLR has an RC on it (10k to Vcc, 47n to Vss, 100R input
> resistance). So it's normally held high and grounded through the
> tact switch. I've done this with just about very other PIC and
> they do reset properly.
>
> On this circuit, the LCD attached doesn't re-initialise. I can tell
> because the power-up display is in two stages and s/w doesn't
> seem to reach that point. No activity is apparent on the dsPIC
> after the switch is pressed, apart from all the I/O I'm monitoring
> going high. Pressing the tact switch 'seems' to do little or nothing.
>
> On any other PIC I would expect to see the LCD re-boot with
> the power-up display message
>
> Very little mention is made in the datasheet of the /MCLR pin,
> which is its only function. I can't find any reference to it in the
> .inc file (eg on other PICs you can turn MCLR on/off)
>
> Right at the start of the project is
>
>          .include "P33FJ64GP802.inc"
>
>   .global __reset             ;program entry point
>   .global __U1RXInterrupt     ;receiver ISR
>   .global __T1Interrupt       ;Timer 1 ISR
>
> and power-up successfully goes through this
>
>            .text
>
>           __reset:
>
> init:      clr     LATA
>            clr     LATB
> etc
>
> Is there something else I need to add ?
>
> TIA
>
> Joe
>
>
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