Using PIC16F877 with FM Transceivers

[nickwch]

Hi,

I am using PIC16F877 @ 16MHz.

I have a pair of FM transceivers (433MHz) that gives CMOS data output.
This data out pin is connected to RC7/RX/DT.

I tried sending a byte 0x41 and correctly received this byte when using wires.
But once I replaced these wires with the pair of transceivers, I received 0xD0.
I do not think its due to noise as I consistenly received 0xD0. Any idea what might be wrong?
Is it because I need to have a pull-up resistor at RC7/RX/DT?

Any help is greatly appreciated.

 

[Nigel Goodwin]

Hi,

I am using PIC16F877 @ 16MHz.

I have a pair of FM transceivers (433MHz) that gives CMOS data output.
This data out pin is connected to RC7/RX/DT.

I tried sending a byte 0x41 and correctly received this byte when using wires.
But once I replaced these wires with the pair of transceivers, I received 0xD0.
I do not think its due to noise as I consistenly received 0xD0. Any idea what might be wrong?
Is it because I need to have a pull-up resistor at RC7/RX/DT?

No, it's because you can't send plain serial data with the radio modules, basically because they are AC coupled. Check my PIC tutorials for more details.