TX module heating up ????

[Jumper]

Maybe you have a 3.3V TX module and run it on 5V... if you connect an mA-meter you can see the consumption and check against the datasheet

[Megahertz]

Maybe you have a 3.3V TX module and run it on 5V... if you connect an mA-meter you can see the consumption and check against the datasheet

It is a 12V module, I am using the same for other 12V running applications as well. It is running smooth there.
I just wanted to confirm that using HSEROUT.... is not playing any part is heating up the module, may be data goes differently or something. I am sorry but my knowledge on the subject is limited so I am trying to erase the possibility of this thing.

Have you used such module with the above statements, could there be any connection in between ?

[mackrackit]

Serial data is serial data. Does not matter if it is generated by hardware or software.

Maybe it is a bad module? Have you tried swapping in another one?

[Megahertz]

Module is heating up because the data pin is high (around 4V) permanently and voltage fluctuates when data is there.
Is it normal when using HSEROUT, is it possible to make the data pin low in standby condition?

[Bruce]

The USART TX pin idles high, so a simple inverter circuit should be all you need to hold the RF transmitters data in pin low during idle periods.

[mackrackit]

The USART TX pin idles high, so a simple inverter circuit should be all you need to hold the RF transmitters data in pin low during idle periods.

Attachment 4465

Then an inverter will be needed on the receiver side also ???

I still think since you are basically building a transceiver you will want a way to turn the transmitter off when not in use. Does the module have an enable pin?

[Bruce]

Then an inverter will be needed on the receiver side also ???

Yes. The same circuit would be needed at the receiving end as well. Assuming the receivers data output idles low, which most do, then it holds the receiving PICs USART data input pin at logic 1, which is the idle input logic for the USART RX pin.

I still think since you are basically building a transceiver you will want a way to turn the transmitter off when not in use. Does the module have an enable pin?

If he's trying to build a transceiver using separate TX/RX modules on both ends, for sure. If you don't shut down the local receiver when transmitting, it takes longer for the receivers front-end to settle & recover from the strong local signal.

[Megahertz]

The USART TX pin idles high, so a simple inverter circuit should be all you need to hold the RF transmitters data in pin low during idle periods.

Attachment 4465

Bruce, is it possible you can draw me a quick circuit I can use on Rx side as well. I have C8050 & C8550, one of them is PNP & the other is NPN, which I can imagine could be used for the above purposes.
My Rx does stay Idle LOW and when data comes the voltage goes high on the data pin. Thanks

[mackrackit]

Mr Google gave this
http://dave.fraildream.net/micro/periph/232-ttl.html
but it is not me.