PDA

View Full Version : problem with ht12e and ht12d



shyam.sunder91
06-12-2010, 09:44 AM
249250

here i hav a problem with ht12e i use the circuit shown

according to the datasheet ht12e when powered the datapins(10-13)are active low ie by default they should be high (is that right??)

but its not happening with me they read zero volts

i get an voltage of 2v at my dout pin

at the rx ht12d the din is reading about 7v(i hav supplied vdd as 9v)

but there is nothing at dout pins of my rx

i use rf tx of 433Mhz and rx the same not the one shown in figure

i hav been struggling with this problem since 10 days im still struggling with that plzzz help

i hav doubt the chip may hav burned off

they cost about 140rs in my area:(

allbits
06-12-2010, 10:55 AM
The HT12E will have a square wave at its output, when it works. It will 'encode' your switch status and send it. The transmit enable pin must be active. The best way to check it, is to use the scope. Getting a 2V at dout is fine, when read with a DMM.

At the receiver side, if you have given a VCC of 9V, its very much possible that you have fried your RX module.
So, try connecting the dout directly to the 12D, with wire, and check the circuit.


And, in your receiver circuit, the address lines are floating. Ground them.

shyam.sunder91
06-12-2010, 01:01 PM
i have powered ht12e and 12d with same supply on single board so as to check the chip

and connected the DataOUT of HT12E directly to DataIN of HT12D

I havn't given any data from data pins(10-13 left open)but at 12d the decoder data out(10-13) are reading 5v each what the reason may be

Actually the HT12E DATA pins(10-13) encoders are active low according to datasheet

forgot to say the HT12D is getting very hot what is this

allbits
06-12-2010, 01:14 PM
Sorry to say this, but i tried to read your reply, but i could not. I would prefer some punctuations. I could have tried to read it again, and try to understand what you might have tried to convey, but i dont have the time for that, and I dont feel like taking the pain for that. If you can reframe with necessary punctuations and explain your wiring, somebody may be able to help.

shyam.sunder91
06-12-2010, 01:35 PM
i have powered ht12e and 12d with same supply on single board so as to check the chip

and connected the DataOUT of HT12E directly to DataIN of HT12D

I havn't given any data from data pins(10-13 left open)but at 12d the decoder data out(10-13) are reading 5v each what the reason may be

Actually the HT12E DATA pins(10-13) encoders are active low according to datasheet

forgot to say the HT12D is getting very hot what is this