wpua

[xnihilo]

wpua=%000001
Will enable pin0 as input with internal weak pull up set (provided individual wpu are set via option_reg).

i sometimes get false trigger that I can't identify. Is it possible that internal wpu are not enough?
Should i add external 10k wpu to make sure i don't get false triggers??

Thanks

[xnihilo]

Nobody has any idea if it is better to use external weak pull ups instead of enabbling pic internal WPU?

[Bruce]

Have you tested this with the external pull-up? My only preference to external VS internal is that I control
current consumption, and, if needed, I can use a stronger pull-up.

[xnihilo]

Have you tested this with the external pull-up? My only preference to external VS internal is that I control
current consumption, and, if needed, I can use a stronger pull-up.

Not tested, it takes more place on the PCB if I use external WPU. I was just wondering if using external WPU would reduce the risks of unwanted triggering of the interrupt on portA change. As you say, I may choose a stronger pull up...

[Bruce]

A stronger external pull-up may help, but it's hard to say without knowing more about your
hardware setup, PIC type, code, etc..

[xnihilo]

A stronger external pull-up may help, but it's hard to say without knowing more about your
hardware setup, PIC type, code, etc..

-> This is a big project actually.
The main board features a PIC16F690. On each porta pins A0 to A4 I connected a TSOP4840 IR sensor demodulator at 40KHz with its 10UF capa and 100 ohms resistor (almost what's recomended in the DS).
When a PWM signal at 40KHz arrives on the sensors, the DATA lead of the TSOP pulls the PIC pin to GND so the PIC can receive the incming signal and decode the 16 bits.
I was just wondering if the internal WPU of the pic are good enough to prevent a false triggering... I didn't find the value of the internal WPU in the PIC DS.