Active low transmitter question

[LEDave]

"WHAT DOES ANY OF THIS HAVE TO DO WITH RECEIVING A TRANSMISSION??!!?!?!??? What do you hope to accomplish??"

mpgmike - I've never mentioned or talked about 'RECEIVING A TRANSMISSION??!!?!?!???' Exactly the opposite. I'm asking if pin3 on the pic is pulled low in code, there will be a wire from pin3 on the pic to the Tx pin on the RF transmitter, the transmitter operates when the Tx pin goes low so I'm asking if I pull pin3 LOW for say 50ms that should make the transmitter transmit.

All I'm trying to do is replicate and replace a push button from the transmitter Tx pin to ground by using a pic to send the Tx line LOW. The 10k resistor being added to keep the line High to stop any floating voltage causing a 'false' transmit.

[mpgmike]

If your question is, "Can the PIC safely overcome the 10k pull-up resistor?", the answer is absolutely yes. Again, will it do what you want, you'll just have to try it and see.

[LEDave]

Thanks for your help mpgmike, anyone else have any thoughts on this?

[richard]

anyone else have any thoughts on this?

using a resistor to drive a pin to a default logic level is not an uncommon practice.
so common that i would not be surprised that your [type not disclosed ] transmitter has such a pullup
resistor already installed. the only reason i could see for an additional pullup would be if the pic was routinely disconnected
from a device that did not have a built in pullup or that an open drain/collector pic pin was in use.
summing up with the detail[almost non existent] you have provided it seems to be a pointless waste of a component
that could easily be eliminated with good programming practice.

[Ioannis]

I think it would be best to have the Data sheet of the that transmitter.

Ioannis

[LEDave]

Hi Ioannis - Looking back at the thread I've done a pretty miserable job of it so far certainly information wise and I apologise to everyone.

*I think it would be best to have the Data sheet of the that transmitter.* For sure, I'll add a screen shot then a full data sheet if needed.

I intend to use maybe a 12F683 to pull a Transmitter Input pin LOW for a few m/s to make it transmit then hold the Tx pin high to stop false triggering via floating voltages if this is safe to do this without damaging the transmitter or pic. I'll add some code as soon as possible, here's the screenshot:

[richard]

I intend to use maybe a 12F683 to pull a Transmitter Input pin LOW for a few m/s to make it transmit then hold the Tx pin high to stop false triggering via floating voltages if this is safe to do this without damaging the transmitter or pic

what is your doubt ?

the data so far indicates no need for pullups , the schematic shows none.

a pic pin when configured as output will never "float" its either high or low when set