problem with sending data using RF module

[rano_zen06]

I never used those ICs... maybe you could some something in this document
http://rentron.com/remote_control/remotes.pdf

It show different value for the resistor. I didn't read the according datasheet to see if it affect anything though.

Maybe you screw the OSC signal with your probe.. use a scope instead, set your probe to 10X (or 100X if you have any) and see what happen.

TE pin should be tied low too unless the oscillator won't run.. as per Their Block Diagram (page 2) in their datasheet.
http://www.holtek.com/pdf/consumer/2_12ev110.pdf

As usual, Before you attach your RF modules, try direct connection, Dout to Din of your Holtek ICs.

HTH

Thanks for the reply.
I already test the holtek IC using direct connection but the result is still the same.No noise but The Rx cannot receive the data and my LCD just show static word "BUS15". Maybe there is something wrong with the code.I post the code below.Can you check it for me??

Tx part

'
' TX code
' =======
'
@ device HS_OSC, LVP_OFF
define OSC 20

DEFINE LCD_DREG PORTC 'LCD data port
DEFINE LCD_DBIT 0 'LCD data starting bit 0 or 4
DEFINE LCD_RSREG PORTB 'LCD register select port
DEFINE LCD_RSBIT 7 'LCD register select bit
DEFINE LCD_EREG PORTB 'LCD enable port
DEFINE LCD_EBIT 5 'LCD enable bit
DEFINE LCD_RWREG PORTB 'LCD read/write port
DEFINE LCD_RWBIT 6 'LCD read/write bit
DEFINE LCD_BITS 8;4 'LCD bus size 4 or 8
DEFINE LCD_LINES 2 'Number lines on LCD
DEFINE LCD_COMMANDUS 2000 'Command delay time in us
DEFINE LCD_DATAUS 50 'Data delay time in us

TransmitterPIN VAR PORTA.0

DEFINE CHAR_PACING 500

TRISA = 0 'Set port A as output
TRISB = 0 'Set port B as output
TRISC = 0 'Set port C as output
TRISD = 0 'Set port D as output

' Define program variables
INCLUDE "modedefs.bas"
col var byte ' Keypad column
row var byte ' Keypad row
key var byte ' Key value
Synk VAR BYTE
Synk = $55

ADCON1 = 7 ' Make PORTA and PORTE digital

low PORTB.6 'Set the R/W bit to low
High TransmitterPin
Pause 500 ' Wait for LCD to start
Lcdout $fe, 1, "Key In Bus ID" ' Display sign on message

loop:
Gosub getkey ' Get a key from the keypad
Lcdout $FE, $C0, "BUS",DEC2 key ' Display ASCII key number
PORTA=KEY
Goto loop ' Do it forever

' Subroutine to get a key from keypad
getkey:
PORTD = 0 ' All output pins low
TRISD = $f0 ' Bottom 4 pins out, top 4 pins in
WHILE PORTD != $F0 : wEND ' Wait 'till all key=up
PAUSE 50 ' Debounce

ScanKeypad:
For col = 0 to 3 '
TRISD=~(DCD COL) ' Set one I/O to output
PAUSEUS 5 ' wait a little bit to avoid
' erratic results
'
ROW=ncd((~(PORTD>>4)) & $f) ' read row
'
IF ROW THEN ' Any key pressed?
key = ((row-1)*4)+ col+1' --- YES convert key value
return ' and getout of here
ENDIF '
NEXT '
Goto ScanKeypad ' No keys down, go look again


Rx Part

'
' RX code
' =======
'
@ device HS_OSC, LVP_OFF
define OSC 20

DEFINE LCD_DREG PORTC 'LCD data port
DEFINE LCD_DBIT 0 'LCD data starting bit 0 or 4
DEFINE LCD_RSREG PORTB 'LCD register select port
DEFINE LCD_RSBIT 7 'LCD register select bit
DEFINE LCD_EREG PORTB 'LCD enable port
DEFINE LCD_EBIT 5 'LCD enable bit
DEFINE LCD_RWREG PORTB 'LCD read/write port
DEFINE LCD_RWBIT 6 'LCD read/write bit
DEFINE LCD_BITS 8 'LCD bus size 4 or 8
DEFINE LCD_LINES 2 'Number lines on LCD
DEFINE LCD_COMMANDUS 2000 'Command delay time in us
DEFINE LCD_DATAUS 50 'Data delay time in us

TRISA = 255 ' PORTA as input
TRISB = 0 ' Set port B as output
TRISC = 0 ' Set port C as output
TRISD = 0 ' Set port D as output

ReciverPIN VAR PORTA.0

ADCON1 = 7 ' Alla digitala

INCLUDE "modedefs.bas"
YourByteVar var byte

low PORTB.6 'Set the R/W bit to low
pause 500 'wait until the LCD initializes
LCDOUT $FE,1, "Receiving Bus ID"

Main:
YourByteVar=PORTA & $0F
Lcdout $FE,$C0,"BUS", DEC2 YourByteVar
GOTO Main

[mister_e]

There's nothing wrong in your code, has to be a hardware problem.

Scope the DO of your Encoder.. anything going out of it?

IF so, erm... why the decoder don't work... mmm let me guess, this Resistor for the OSC? Could be, did you tried with both value in the first PDF i sent you?

[Bruce]

Have you tested the HT-12E directly wired to the HT-12D (with a common ground), without
a microcontroller in the circuit, and still seen no response on the decoder outputs?

If the direct-connect test fails, then I would suspect one of the following;

1. You have a different address on the decoder than what's set on the encoder.
2. You have no common ground between the two ICs.
3. You have a bad encoder or decoder.

The encoder data out to decoder data in is the 1st test we recommend to anyone having
problems. This test helps determine if the problem is with the encoder/decoder ICs or the RF
stage.

[mister_e]

Bruce, just for curiosity sake, what happen if all addresses pins are left open?

[Bruce]

Hi Steve,

Most Holtek encder/decoder ICs have internal pull-ups, so floating these pins is the same
as connecting them to Vcc. This should be in the data sheet. The 8-bit series are tri-state.

But I never allow them to float. Especially in an application with an oscillator or embedded
controller that's going to indroduce a ton of digital switching noise to the power supply rails.

I've only seen maybe 1 in 10K failures with a set of Holtek encoder/decoder ICs. 9 times out
of 10 it's something simple like noise, a single bit difference in the address, bad connection,
wrong oscillator resistor value (voltage dependant), or just plain wired wrong that's the
cause of failure.

[mister_e]

As you know, i'm not a "left unused pin floating" fan. Was just for my own curiosity.. yeah datasheet says it could be left unconnected but.. erm...

[rano_zen06]

There's nothing wrong in your code, has to be a hardware problem.

Scope the DO of your Encoder.. anything going out of it?

IF so, erm... why the decoder don't work... mmm let me guess, this Resistor for the OSC? Could be, did you tried with both value in the first PDF i sent you?

I use absolutely the same value of resistor in the PDF but the encoder/decoder still not function with direct connection.I can assure that Both Ground,Dout and Din pin was connected in the right position after chek it a few times. I'm curious about "transmitterPin Var portA.0"..
Do I need to put it in my program if use HT12E and HT12D ?

[mister_e]

There's no real big deal with that var, the only thing is HIGH TransmitterPIN at the begining... but this should send you some data at the begining, says your receiver should show BUS01 untill you press on your Keypad. no real harm at all...

[rano_zen06]

I already check my Dout and Din pin at HT12E/HT12D using Oscilloscope but the result show nothing .Only a long straight line shows at scope.It means No output/input from my HT12E and HT12D either I'm using direct connection or not.The resistor value for my OSC pin is exactly the same with what is listed in rentron pdf. But mr.Bruce said earlier that the resistor's value depends on voltage supply at HT12E/HT12D .So I check my voltage supply at vcc pin and I got 5.04 for HT12E and 5.06 for HT12D.Actually how to calculate the resistor value for OSC if it's really depends on voltage supply??

[mister_e]

Shouldn't be that critical for few millivolts. Are your Encoder/decoders address pins tied to ground as in the document i sent?

[Bruce]

You'll see a chart in the data sheet for the HT12E and HT12D that shows how to select
oscillator resistor values.

I normally use 33K for the decoder when operating at 5 volts. Locate 5 volts on the
bottom of the chart in your HT12D data sheet, and follow the vertical line up to where
the line from 33K on the right crosses it.

This indicates just a tad >200kHz internal oscillator speed at 5 volts with 33K.

Now look just below the chart where it states The recommended oscillator frequency is
fOSCD (decoder) should be about equal to 50 x fOSCE (HT12E encoder).

Now follow the vertical line up from 5 volts in the HT12E data sheet to where the line
from 750K crosses. Just short of 4kHz.

With +/- 5% resistors, you're in the ball-park.

If you have a scope you can experiment a bit with oscillator resistors to see the effect
changing them has on the encoder data output signal.

At any rate, if you're getting nothing on the data output pin of your HT12E when /TE is
at ground, then I would suspect you have a bad encoder.

[rano_zen06]

Shouldn't be that critical for few millivolts. Are your Encoder/decoders address pins tied to ground as in the document i sent?

Yes.All the Address pin for both encoder/decoder was tied low. I also connect the TE pin to GND for HT12E,but still no data receive at Rx. I'm not assuming that both encoder/decoder is damage because I have extra pair for HT12E and HT12D. when I use it, the result is same with the previous pair I have.the Holtek's data sheet say that the VT pin at HT12D will goes high to indicate valid transmission but my VT pin always LOW.