rfPIC Serin problem

[gavo]

Hi All, I have been having some problems trying to send and receive data using the rfPIC16F675K and the rfRXD0420, I have been trying to use the serin command to read the data i have sent using the serout command:

pulsout porta.2, 1
SerOut PORTA.2,n2400,[$55,$55,"A",B0]

when I use the serin2 command to wait and to receive "A", it seems like it does not work

SERIN2 PORTC.1,n2400,1000,loop1,[WAIT("A"),B1]

i have also tried the pulsin command but seem to be getting nothing, does anyone have some ideas?

Many Thanks,

Gavin

[mister_e]

This should work... but as we don't se the whole code, it's hard to tell if you don't have anything missing in it. Make sure you have disabled all analog stuff on the pin you're using and it should be ok... unless i missed something

[gavo]

Hi Steve,

Many thanks for the reply ;-)

Please find below:

Transmitter Side

INCLUDE "modedefs.bas"
DEFINE OSCCAL_1K 1

TRISIO.0 = 1 ' set GPIO.0 as input
TRISIO.2 = 0 ' set GPIO.0 as output

B0 VAR WORD

start:

PAUSE 500
HIGH PORTA.5
PAUSE 500
LOW PORTA.5
PAUSE 500
HIGH PORTA.5
PAUSE 500
LOW PORTA.5
GOTO loop

LOOP:

PAUSE 500
LOW PORTA.5
IF PORTA.3 = 0 THEN GOTO LOOP1
IF PORTA.3 = 1 THEN GOTO loop

LOOP1:

HIGH PORTA.5
SerOut PORTA.2,n2400,[$55,$55,"A",B0]
Pause 100
GoTo LOOP

End
INCLUDE "modedefs.bas"


trisa = %00111111
trisc = %00111111

B0 VAR WORD
B1 VAR BYTE
B2 VAR BYTE
Pause 100

start:

high porta.4
low porta.1
pause 500
low porta.4
high porta.1
pause 500
high porta.4
low porta.1
pause 500
low porta.4
high porta.1
pause 500
GOTO loop

loop:

SERIN2 PORTC.1,N2400,1000,start,[WAIT("A"),B1]
GOTO LOOP2

loop2:

low porta.4
high porta.1
pause 3000
high porta.4
low porta.1
pause 3000
goto START


End

Receiver Side:

[gavo]

Hi steve,

I have been running the code again and it seems to get stuck on the the receive side in the line of:

SERIN2 PORTC.1,T2400,1000,start,[WAIT("A"),B1]

The code seems just to hang, it does not even run to the label "start" i am using the PIC16F676, any ideas why it is doing this?

Regards,

Gavin

[Bruce]

PORTC.1 on the 676 is an analog input by default at power-up. It will always read 0 until
you disable its A/D function.

The rfPIC12F675K also has A/D you may need to disable.

[gavo]

Hi Bruce,

Many thanks, i will try that ;-)

Regards,

Gavin

[gavo]

Hi Bruce,

I have used the ANSEL = 0 and the device works until I plug the receiver board in, when I plug the receiver board in the device "seems"to hang, I then put a scope on RC1 and noticed quite a crazy waveform, I then pressed the button on the transmitter and it took around +- 20 sec's before the receiver recognised the transmitter's data and then the device functioned correctly. I am assuming I have something wrong with my transmitter serout routine as I am not sure why it take so long for the receiver to recognise the transmitter, have you some ideas?

Many Thanks,

Regards,

Gavin

[Bruce]

Hi Gavin,

I'm just guessing, but are you using a Microchip rfPIC dev kit?

[Bruce]

I'm assuming this is the hardware you have, so I broke out my rfPIC eval kit, and played
a bit. Give these a try.

Receiver example;

'****************************************************************
'*  Name    : rfPIC_RX.BAS                                      *
'*  Author  : B. Reynolds                                       *
'*  Notice  : Copyright (c) 2007 Reynolds Electronics           *
'*          : All Rights Reserved                               *
'*  Date    : 10/09/2007                                        *
'*  Version : 1.0 (Momentary decoder version)                   *
'*  Notes   : 2-Bit decoder for Microchip RF dev system         *
'*          : with rfRXD0420 module installed in PICkit 1 board *
'****************************************************************
@ DEVICE PIC16F676,MCLR_OFF,INTRC_OSC_NOCLKOUT,WDT_OFF,BOD_OFF
@ DEVICE PWRT_ON,PROTECT_OFF
    
    DEFINE OSC 4
    DEFINE NO_CLRWDT 1      ' Watchdog timer is disabled, so we don't need to reset it
    DEFINE OSCCAL_1K 1      ' load factory calibration value
    DEFINE INTHAND RESET_VT ' Interrupt on Timer1 overflow to reset outputs in 65.5mS
                            ' if no serial data received in this time period
    SYMBOL  D_IN = PORTC.1  ' data input pin
    SYMBOL  TMR1IF = PIR1.0 ' Timer1 overflow interrupt flag (reset in int handler)
    SYMBOL  TMR1IE = PIE1.0 ' Timer1 interrupt enable bit
    
    'Variables for saving state in interrupt handler
    wsave   VAR	BYTE $5F system	   ' Saves W
    ssave   VAR	BYTE bank0 system  ' Saves STATUS
    psave   VAR	BYTE bank0 system  ' Saves PCLATH
    fsave   VAR	BYTE bank0 system  ' Saves FSR
    
    ' Working variables
    MATCH     VAR BYTE bank0 system ' Match variable
    DAT_OUTB  VAR BYTE  ' Holds decoded data for output
    DAT_IN1   VAR BYTE  ' 1st Data byte
    DAT_IN2   VAR BYTE  ' 2nd Data byte for verify
    CHK_SUM   VAR BYTE  ' Holds checksum received
    CheckSum  VAR BYTE  ' Computed checksum of all bytes received
    LOOPS     VAR BYTE  ' Loop var
    
    ' Constants
    Synch    CON "~"    ' 01111110 synch byte
    N2400    CON 16780  ' 2400 bps inverted
    N4800    CON 188    ' 4800 bps inverted
    
     ' hardware init
    PORTA = 0
    TRISA = %00111001   ' RA1 and RA2 are LED outputs
    PORTC = 0           ' Clear outputs on power-up
    TRISC = %00111110   ' RC1 = RF input
    IOC = 0             ' Interrupt on change disabled
    VRCON = 0           ' Comparator Vref disabled
    CMCON = 7           ' Disable comparators
    ANSEL = 0           ' disable A/D
    OPTION_REG = 128    ' Pull-ups off
    
    ' Setup Timer1 for resets after ~65.5mS
    T1CON = %00000000   ' Internal clock, 1:1 prescale, Timer1 off for now
    TMR1L = 0 
    TMR1H = 0           ' Timer1 low & high bytes cleared
    TMR1IF = 0          ' Clear Timer1 overflow flag before enabling interrupt
    TMR1IE = 1          ' Enable Timer1 overflow interrupt
    INTCON = %11000000  ' Global & peripheral ints enabled
    MATCH = 0           ' Clear match count
    GOTO    MAIN        ' Jump over int handler
    
ASM  ; Timer1 overflow interrupt resets outputs when no valid key press
     ; is detected within ~65mS
RESET_VT
    movwf  wsave	 ; Save W
    swapf  STATUS, W     ; Swap STATUS to W (swap avoids changing STATUS)
    clrf   STATUS	 ; Clear STATUS
    movwf  ssave	 ; Save swapped STATUS
    movf   PCLATH, W     ; Move PCLATH to W
    movwf  psave	 ; Save PCLATH
    movf   FSR, W	 ; Move FSR to W
    movwf  fsave         ; Save FSR
    
    ; Do interrupt stuff here
    bcf    T1CON,TMR1ON  ; Stop Timer1
    clrf   TMR1L         ; Clear low byte
    clrf   TMR1H         ; Clear high byte
    bcf    PIR1,TMR1IF   ; Clear Timer1 interrupt flag bit
    clrf   PORTA         ; Clear outputs on button release
    clrf   MATCH         ; Clear match variable
    
    ; Restore FSR, PCLATH, STATUS and W registers
    movf    fsave, W	 ; retrieve FSR value
    movwf   FSR		 ; Restore it to FSR
    movf    psave, W	 ; Retrieve PCLATH value
    movwf   PCLATH	 ; Restore it to PCLATH
    swapf   ssave, W     ; Get swapped STATUS value (swap to avoid changing STATUS)
    movwf   STATUS	 ; Restore it to STATUS
    swapf   wsave, F	 ; Swap the stored W value
    swapf   wsave, W	 ; Restore it to W (swap to avoid changing STATUS)
    bsf     T1CON,TMR1ON ; Re-enable Timer1 before exiting interrupt handler
    retfie		 ; Return from the interrupt
ENDASM
 
MAIN:          
    ' Fire up Timer1 before entry to serial input routine
    T1CON.0 = 1
    
    ' at 4MHz Timer1 overflows in 65536 * 1uS (~65.5mS) if no Synch byte
    ' and serial data arrive on time. SERIN2 timeout & label options
    ' are useless with a noisy RF receiver output - as noise continually
    ' resets the timeout period causing it to hang forever.
    
    ' Wait for Synch byte, then get new inbound data & checksum
    SERIN2 D_IN,N2400,[WAIT(Synch),DAT_IN1,DAT_IN2,CHK_SUM]
    
    T1CON.0 = 0    ' Stop Timer1 once we've received data
    TMR1L = 0      ' Clear low byte
    TMR1H = 0      ' Clear high byte
    
    ' / **** Begin data validation **** /
    
    ' Calculate checksum by adding 2 data bytes together
    CheckSum = DAT_IN1 + DAT_IN2
    
    ' Test new checksum against one received in CHK_SUM
    IF CheckSum != CHK_SUM THEN MAIN ' Failed checksum, return
    
    ' Test data bytes for match
    IF (DAT_IN1) != (DAT_IN2) THEN MAIN ' Failed data comparison, return
    
    MATCH = MATCH + 1        ' We have a match so increment match count
    IF MATCH = 2 THEN DECODE ' Everything matched twice, we're good
    GOTO Main                ' Else do it all over
    
    ' Everything looking good - so place new data on outputs
DECODE:
    ' Place decoded values on port pins..
    PORTA = DAT_IN1 & %00000110
    DAT_IN1 = !DAT_IN2  ' Destroy the match
    MATCH = 0 
    GOTO MAIN
        
    END

Transmitter example;

'****************************************************************
'*  Name    : rfPIC_TX.BAS                                      *
'*  Author  : B. Reynolds                                       *
'*  Notice  : Copyright (c) 2007 Reynolds Electronics           *
'*          : All Rights Reserved                               *
'*  Date    : 10/09/2007                                        *
'*  Version : 1.0                                               *
'*  Notes   : 2-BIT Encoder for remote control with the         *
'*          : rfPIC12F675 on Microchip rfPIC demo board         *
'****************************************************************
@ DEVICE PIC12F675,MCLR_OFF,INTRC_OSC_NOCLKOUT,WDT_OFF,BOD_OFF
@ DEVICE PWRT_ON,PROTECT_OFF
    
    ' With rfRXD0420 module installed in PICkit 1 board;
    ' SW1 toggles LED D6 on PICkit 1 board
    ' SW2 toggles LED D7 on PICkit 1 board
    DEFINE OSC 4
    DEFINE NO_CLRWDT 1
    DEFINE OSCCAL_1K 1
    
    SYMBOL D_OUT = GPIO.2 ' RF serial data output
    SYMBOL E_OUT = GPIO.5 ' RF transmitter enable output
    
    DAT_OUT VAR BYTE    ' Holds 8-bit data byte
    LOOPS   VAR BYTE    ' Loop var
    CHK_SUM VAR BYTE    ' Holds calculated checksum of outbound data
    BAUD    VAR WORD    ' Holds baud rate
    
    ' Constants
    PreAmble CON $A5    ' 10100101 preamble
    Synch    CON "~"    ' 01111110 synch byte
    N4800    CON 188    ' 4800 bps 
    N2400    CON 16780  ' 2400 bps
    GUARD    CON 5      ' 5mS guard time pause
    
    ' hardware init 
    GPIO = 0            ' Everything off on boot
    ' GPIO.2=data out, GPIO.5=RF enable, GPIO.3,4=SW1/SW2 switch inputs (rfPIC board)
    TRISIO = %00011011  '
    ANSEL = 0           ' Disable A/D
    INTCON = %00001000  ' Enable port change wakeup from sleep
    WPU = %00010000     ' pull-up on for GPIO.4 (external pull-up already on GPIO.3)
    IOC = %00011000     ' Wakeup on change enabled for GPIO.3,4
    VRCON = 0           ' Disable internal Vref
    CMCON = 7           ' Disable comparators
    OPTION_REG = 0      ' Pull-ups on
    
    D_OUT = 0           ' Idles low for inverted serial output
    E_OUT = 0           ' Enable for RF transmitter=0 (transmiter off)
    BAUD = N2400        ' Set baud rate here
    
Main:    
    ' Read port to clear missmatch, if with no buttons pressed, then
    ' clear int-on-change flag & snooze until wake up on change. This
    ' conserves battery power on the demo board with 3V coin cell.
    IF (GPIO.3=1) AND (GPIO.4=1) THEN ' pins will be 0 only when buttons are pressed
     E_OUT=0         ' Disable transmitter
     INTCON.0 = 0    ' No buttons down, so clear int on change flag
     @ SLEEP         ' and start snoozin..zzzzzzzzzzz
     @ NOP           ' Do nothing for 1st instruction on wake-up
    ENDIF
    E_OUT=1          ' Enable transmitter (+ lights RFEN LED on demo board)
    PAUSEUS 25       ' Allow RF stage to stabilize
    
    ' Button pressed (or being held down), so keep going   
Encode:  
    ' Only DAT_OUT bits 1 and 2 are used. We add a few 1's in bit
    ' positions 0,3,5,7 to balance out the data packet being sent.
    DAT_OUT = %10101001
    ' Get data on button inputs & invert 0's to 1's
    DAT_OUT.0[1]=~GPIO.3
    DAT_OUT.0[2]=~GPIO.4
    INTCON.0 = 0  ' Clear int on change flag
      
    ' Build checksum of 2 data bytes
    CHK_SUM = (DAT_OUT * 2)
    
Transmit:
    SEROUT2 D_OUT,BAUD,[PreAmble,Synch,DAT_OUT,DAT_OUT,CHK_SUM]
    PAUSE GUARD ' 5mS guard time gives decoder time to respond,calculate,change,etc.
    
    GOTO Main
        
    END

You should be able to modify these pretty easily for your own application.

[gavo]

Hi Bruce,

Many thanks I will give it a bash ;-), regards, Gavin

[onepiece]

Hi,

I'm a beginner in PIC programming and now struggling to program rfPIC12F675. I'm confused on how TRISIO assign input and output.

movlw b'00010000' ; set GP<4> as digital inputs and other bits as output
movwf trisio ; and set others as outputs/mclr/clkout/osc

However, when I try to simulate it, and try to observe the output (we fire the GP4 as high),
it seems that the output is 0 all the time.

Other than setting the trisio, do I need to call any other instructions to make sure the data is being read in - send to modulation - and then output accordingly.

I'm a bit lost now. Hope that you can help

[Bruce]

The data sheet has everything you're looking for.

And if you're looking for examples in Microchip assembler, then check the Microchip website for rfPIC examples. Here's a direct link to rfPIC examples; http://www.microchip.com/stellent/id...cName=en010060

[onepiece]

Thanks for that. It is useful!

[medusa2584]

im looking at the demo program for development kits transmitter and receiver rfpic12675 and receiver rf rxd XXX. im trying to apply the same program to my telemtry project but with digital input.

i dont understand the part of program which under head transmitter loop. do we need to do the loop if our input is digital? and what about the '' rrf ' and 'bnz' instruction? rotate right flag?

i don't understand the TZnextbit too? im so lost right now. can anyone explain this to me?

thanks

[Bruce]

Help for rrf; PIC data sheet.

Help for bnz assembly language pseudo-instruction; MPASM help file.

Help with assembly language/code examples for rfPIC; http://forum.microchip.com/tt.aspx?forumid=166

Knowing where to look; priceless

For everything else; there's MasterCard....;o}

[onepiece]

Not only mastercard....
Having to learn from an expert.....much more priceless....

[Bruce]

We have a CD-ROM with PicBasic Pro code examples on this page http://www.rentron.com/QRELAY.htm that we offer for a modest fee of $39.95.

Two of the simple PBP code examples on this CD have generated > 100K $ in sales of tiny little 8-pin PIC micros. In less than 1 year. That's why we don't give this stuff away for free..;o}

It may seem super simple once you have the source code, but it's a different story when you write each routine from scratch. And test each routine on 50 or so RF transmitters & receivers to make sure they actually work with various RF modules.

Like Melanie recently said, it's not what you have, but how you use it. She really does know what she's talkng about..;o}

Even when she only hints.

[chuck]

Bruce do you have a distributor in the uk ?

for the CD-rom

[Bruce]

Hi Chuck,

Sorry, but we don't have any distributors for this CD. If postage is outrageous to your location, we can pop one in the regular mail for you.

[medusa2584]

does anyone know how to calculate the transmission bitrate for rfPIC12F675?

and im confuse about one thing. if the datasheet says it would transmit data in 433.9 mHZ, is that referring to the frequency band or the carrier frequency.? as far as i understood, it is the frequency bandwidth, and the carrier frequency depending on the oscillator that we used. isn't it??? can anyone please confirm this to me??

do you know the range of data can be transmitted by rfPIC12F675??

thank you in advance

[Bruce]

The transmit frequency = RFXTAL frequency * 32. This can be trimmed by the value of C1 as shown in the chart. This is the carrier frequency for ASK modulation.

ASK transmits at the center frequency. FSK transmits a few kHz from center frequency. This is explained in the data sheet.

The bit-rate data is transmitted at depends on your firmware. If you look at the Microchip code examples you'll see how they use delays between toggling the data pin to set the bit- rate. 40 kbps is the upper limit.

What you'll have for operating range will vary like the wind depending on your finished RF design, voltage on the PS pin, and a boat-load of other factors like receiver sensitivity, operating environment, antenna design/selection, etc, etc,.

[medusa2584]

thank you very much for the reply..

i have one more question..im testing the rfPIC development kit right now with the demo program..we are trying to test the rf12F675 by using oscilloscope by conneting the probe to the pin output which is pin GP5 and GP0. however, we see no signals output from the transmitter except the analog voltage value 1.29 mv which i think comes from the power supply.

any suggestion how to test it? we have checked the connection circuit many times..but it still give us the same result

[Bruce]

You must have a different rfPIC development kit than the one I have. GP0 on mine connects
to POT0. GP5 to the RFENA pin?

Here are the pin definitions in the Microchip demo tx code example;

#define POT0 GPIO, 0 ; (Analog Input) Potentiometer GP0
#define POT1 GPIO, 1 ; (Analog Input) Potentiometer GP1
#define TXD GPIO, 2 ; (Output) Transmit Data
#define PB3 GPIO, 3 ; (Input Only) Push button switch GP3
#define PB4 GPIO, 4 ; (Input) Push button switch GP4
#define RFENA GPIO, 5 ; (Output) RF Enable

I also have a full schematic in .PDF format on my CD that verifies this.

Have you tried placing the scope on GP2?

[medusa2584]

yup we did try..but we dont get the expected signal..

am i right if im expecting a modulated signal came out from the output channel? so i should be able to see an analog modulated signal with ASK. but, we only see a digital signal 0 1 which i think comes from the power supply that we used.

im sorry..i gave the wrong information. we are using the same develoment kit as yours

thank you

[Bruce]

we only see a digital signal 0 1

You should be seeing a digital signal if you're placing a scope probe on GP2. This is a digital
I/O-pin connected to pin #14 DATAask on your tx board. That's your outbound data being
used to control the PA.

Read the data sheet, section 9.4, ASK Modulation and you'll see why an I/O-pin
would be connected to pin #14.

You can find a modulated signal on the antenna output, but you'll be loading it with your
scope probe.

[onepiece]

Hi
I would like to test whether my rfpic12f675 an rfrxd0420 works according to the demo for the development kit. The part for LED indicators on the Pickit Flash 1, it says that when my GP buttons on transmitter are pressed, LED will be lite up. Does that mean that we can just verify this through the dev kit? The LED on my board sometimes toggle when I press the switches, and I thought I should have got a 7 LEDs to light up.
I'm confused at the part where I need to use PIC16f676 for the rxrfd420, do I need to connect the pins RA5 to RC 2 to the PIC itself? Can anyone help me please.

[Bruce]

Read the rfPIC Dev Kit Quick Start Quide. It has blow-by-blow instructions. The link above
will take you directly to the page where you can download this if you don't already have it.

[medusa2584]

yes..we finally manage to test the rfkit and it works..

now its the time for me to alter the code..the transmitter right now required no external input except from the switch to operate. we planned to replace the gp4 with input from sensor and the input is digital . however there are some part of the demo program that i dont understand the purpose which i pasted below.

under part "fill in transmission buffer" , why they purposely inserted the random number into the buffer register?and then will be ignored by receiver ? and how the receiver is going to ignore it?

and since the input for this demo is analog signal, they have used the converter and have the result stored in register ADRESH and ADRESL. so as for me who has a digital input, i should be able to read straight from the gpio port , but im not sure how is the command since im only read from one bit of register.



and this command means the input data being read and stored in temp register?

the part of demo program that im confused

;----------------------------------
; fill in transmission buffer
;----------------------------------

XMIT

bsf RFENA ; Enable Transmitter

movlw 0x73 ; send Serial number
movwf CSR0

movfw FuncBits ; send Function Bits
movwf CSR1

; send 16-bit Counter
;
; send analog value (this is modified from the fixed
; KeeLoq(r) protocol; these two fields are normally
; used for 16-bit counter value)

bsf STATUS, RP0 ; ----- Select Bank 1 -----
movfw ADRESL ; ADRESL Result
bcf STATUS, RP0 ; ----- Select Bank 0 -----
movwf CSR2

movfw ADRESH ; ADRESH Result
movwf CSR3

movlw 0x56 ; send 32-bit serial number 1 (ignored by receiver)
movwf CSR4

movlw 0x34
movwf CSR5

movlw 0x12
movwf CSR6

movlw 0x20
movwf CSR7

movlw 0x55 ; send Flags
movwf CSR8

[onepiece]

I think I have the same problems with gavo. But currently I'm using assembly to do my programming. This rfPIC12f675 is different from other normal PICs where it has only one tris and gpio port. And the gpio reg is assigned to the pin itself.
Can you kindly explain to me about how can I read in data serially using assembly? I'm sorry that I'm not really familiar with the code you pasted before.
Can I just read in data bit by bit say into gp3 and then send it to gp2 for ASK modulation?
Or can I just put or connect my digital input to gp2?

I understand that the coding below is a Keeloq protocol

' Constants
PreAmble CON $A5 ' 10100101 preamble
Synch CON "~" ' 01111110 synch byte
N4800 CON 188 ' 4800 bps
N2400 CON 16780 ' 2400 bps
GUARD CON 5 ' 5mS guard time pause

As I'm not familiar with your coding, may I know what CON indicates and what N4800 CON 188 means?


Thanks again for your help!

[mister_e]

in PBP, CON is used to define a software constant, in asm it should looks like

YourConstantVariable = .25

or
#DEFINE YourConstantVariable .25

Using pre-defined constant here and there, allow to have a better readable code, and also allow to do some changes without having to scroll the whole code.

For a 12F675 asm example.. well, first google hit gave me
http://www.jbgizmo.com/page29.htm

[medusa2584]

hi people,

has anyone ever encountered a problem of stack overflow in their program?
rite now im doing a program to transmit a stack of data which contain 16 bit + 64 bit +

and the pic that im using is a pic12f675. what should i do to reduce this error?

[BobK]

Hi Medusa,

I had this problem once and it turned out to be a subroutine that had a GOTO at the end of it instead of RETURN. Changed the word--solved the problem.

HTH,

BobK

[medusa2584]

thanks bobk..i tried that, put return at the end of each goto instruction i have, but still it has not succeeded. is it possible due to overflow stack?

my program is supposed to have a stack of 8 byte output excluding the preamble and header and timeguard.

does anyone ever write a program that has a subroutine as follows

read input from port GPIO
move data from GPIO to 'input' register
take only data from bit 1
store the input (bit 1)to bit 0 at another register

repeat for eight times

what i already have in mind

movfw GPIO
movwf input
movlw 0000 0000
xorwf input,f
goto rotate

rotate
rrf input,f
rrf input,f

anyone has any idea to continue?

[BobK]

Hi Medusa,

That's not what I meant. If you are calling a subroutine then at the end of the subroutine you put a RETURN. GOTO does not go at the end of a subroutine. This was the problem I had with one of my projects (18F452). The stack overflow was causing my project to hangup when it got to the subroutine after the stack overflowed. This was the only point I was trying to make.

If you have both a GOTO and a RETURN then you might still be experiencing a problem.

HTH,

BobK

[hell_pk]

Hi Bruce!
I have tried ur codes on RfPIC kit. i can see the data being sent by transmitter on GP2 and received on PORTC.1 on receiver side but the LED's are not blinking. what might be the problem.plz help me troubleshoot.
thanks

[Bruce]

That's hard to say. It works perfectly on my rfRXD0420 module installed in PICkit 1 board.

Are you compiling the receiver code without any changes, and programming it into a
PIC16F676 on the PICKit 1 board with the rfRXD0420 installed per the instructions?

[hell_pk]

Hi
U have not included modedefs.bas in ur program.is that an issue?
I did that but to no avail.
maybe config fuses are causing something.they seem ok.they are as under when i read them using PICkit 1 software:
12F675
config word:0x31D4
osccal: 0x3480
bandgap: 0x3000

12F676
config word:0x31C4
osccal: 0x3440
bandgap: 0x3000

[onepiece]

Hi there,

I've altered the receiver_demo program to suit my application. - I took in the data from rfRxd0420 drom RC2 and try to take it out serially from RC0 of the pic16f676 so that I can
probe the data transmitted.

Currently, I'm simulating the program using MPLAB IDE. Pardon me if I'm wrong.
The receive_demo program that I understand, will check for header. But,
it does says that if the data is high before 6ms, therefore the header is valid.
What if the data is also 'LOW'?
I'm actually having problems with simulation coz it does not want to
come out of the loop - unless I put '1' in between.

When it came out of the loop, I should be able to record that and then output that
to the RC0 but it seems that the program didn't even jump to search for a guard time,
instead it continue the process to find for high or low pulse.

I just altered the receive demo of the dev kit. Can anyone help me please?
Or do you suggest a better way to simulate this program?

MAIN
call CLOCK ; to update TRMLOW and TMRHIGH
; TMRLOW ~=4us TMRHIGH ~=1ms

movlw HIGH STATEM
movwf PCLATH
movf STATECNTR, W ; Mask out the high order bits of
andlw B'00001111' ; STATECNTR (a noise guard)

addwf PCL, F ; The program clock (PCL) is incre-
STATEM
; check for possible start of data stream
goto BEGIN ; mented by STATECNTR in order
goto BEGIN1 ; to go to the appropiate routine
goto HEADER ; header is being ignored
goto HEADER1 ; just count up the time and then takes the data
goto HIGHPLSE ; times the width of Hi Pulse
goto LOWPULSE
goto RECORD ; record the 8 byte data
goto WAIT4END ; wait for guard time to be greater than 8ms

goto FIRST0 ; check whether DATA0 of bit 0 is 0 or 1
call SENDOUT ; to send out the serial data out through portc pin 0
goto RESET ; These RESET commands correct
goto RESET ; erroneous values of STATECNTR
goto RESET ; not caught by the mask above.
goto RESET
goto RESET
goto RESET

[medusa2584]

from the demo program, they used ASK modulation which use NRZ format modulation.
in this format, when the input is zero it would give you a pulse of 110 while if the input is one, it would give pulse 011, which means it will still give you pulse high for whichever input.

[medusa2584]

im still experiencing this overflow stack error message..
ive tried to change all goto to call instruction
put return for every subroutine..but still it doesnot work
can anyone help me

i pasted my full program below

;nur azrin hilmi
;gdp 17-telemetr 


    LIST   		P=RF675K       ; list directive to define processor
 	#include    <RF675K.INC>  ; processor specific variable definitions


;**************define variables*********************************

	#define	sensor	GPIO, 1
	#define txd     GPIO, 2             ; (Output) Transmit Data
	#define pb3     GPIO, 3             ; (Input Only) Push button switch GP3
	#define pb4     GPIO, 4             ; (Input) Push button switch GP4
	#define rfena   GPIO, 5             ; (Output) RF Enable

 	; GPIO Pins =    xx543210
;	#define gptris b'00011011'

	#define TGUARD  d'5'
	#define exor 	b'00000000'	
	#define	total d'8'
;	#define	rtime d'5'
;***************************************************************

	org  0x00
	goto initialize
	
	org  0x004
	
	movwf	w_temp
	swapf	STATUS,W
	bcf		STATUS, 5		;select bank 0
	movwf	status_temp		;save status register
;***************************************************************

;	interrupt service routine (ISR)
;   interrupt on change on pin of gpio

	movfw	GPIO
	bcf		INTCON,0
	
;**************************************************************

	swapf	status_temp,w	;set bank into original state
	movwf	STATUS
	swapf	w_temp,F
	swapf	w_temp,W
	
	retfie


;***************************************************************

WaitxTE
        movwf   Count2      ; [1]

waitxlp            
        movlw   D'30'       ; [1]
        movwf   Count       ; [1]

wait400lp
      nop                 ; [1]

      nop                 ; [1]
    decfsz  Count,F     ; [1]
    goto    wait400lp  ; [2]
;                          --------
;                         79 x 5 = 395us

     decfsz  Count2,F    ; [1]
    goto    waitxlp    ; [2]

     retlw   0           ; [2]

;                       total 2 (call) + W x (395 + 5) + 2 (return)
;                       w = 1 -> 406us @4MHz
;                       w = 2 -> 806us @4MHz
;*************************************************************
;initialize pic
;*************************************************************

initialize

;clearing all ports
	CLRF	nobit
	CLRF	nobit2
	clrf	input
	clrf	store
	clrf	rotateright
	clrf	Count
	clrf	Count2
	clrf	ltime
	clrf	rtime
;disable global interrupts during initialization

	bcf     INTCON,7

;calibrating the internal oscillator

;	bsf     STATUS,5		;select bank 1
	call	0x3FF
	movwf	OSCCAL		
;	bcf		STATUS,5
	
;turn off the comparator
	bsf		STATUS,5

	clrf 	ANSEL			; clear ansel register
	bcf		STATUS,5
	
	clrf 	GPIO			; initialize General Purpose Input Output to 0
		
;setting gpio register to the cosrresponding io pin
	bsf 	STATUS,5
	
	bsf		TRISIO,0
	bsf		TRISIO,1
	bsf		TRISIO,4
	bcf		TRISIO,2
	bCf		TRISIO,5

	bcf     STATUS,5		;select bank 0

;set bit 0:2 at register cmcon	;setting gp2 as digital output |offkan comparator
	bsf		STATUS,5
	bsf		CMCON,0
	bsf		CMCON,1
	bsf		CMCON,2
	BCF		STATUS,5
; VRCON	register ; CVref circuit powered down,no Idd drain

	bsf		STATUS,5
	bcf		VRCON, 7
	bcf		STATUS,5


;****************************************************************
;****timer1 module gate control**********************************
; disabling timer1
	bsf		STATUS, 5		; select Bank 1
	movlw   b'01000100'		; disable TIMER1
	movwf	T1CON		;
	bcf		STATUS, 5		; select Bank 0

;****************************************************************
;weak pull-up register (wpu)
;each pull-up is automatically turned off when the pin is configured as an output
	bsf     STATUS,5
	movlw	b'00010000'
	movwf	WPU
	bcf     STATUS,5

;***************set pin for config_address regsiter

;OPTION Register 

;   OPTION_REG contains control bits to configure:
;   Weak pull-ups on GPIO (see also WPU Register above)
;   External GP2/INT interrupt
;   TMR0
;   TMR0/WDT prescaler

        bsf     STATUS,5	         	; ---- Select Bank 1 -----

        bcf     OPTION_REG, NOT_GPPU  	; GPIO pull-ups: enabled

        bsf     OPTION_REG, INTEDG  	; Interrupt Edge: on rising edge of GP2/INT pin

        bcf     OPTION_REG, T0CS    	; TMR0 Clock Source: internal instruction cycle (CLKOUT)
        bcf     OPTION_REG, T0SE    	; TMR0 Source Edge: increment low-to-high transition on GP2/T0CKI pin

        bcf     OPTION_REG, 3     		; Prescaler Assignment: assigned to TIMER0

        ; TMR0 Prescaler Rate: 1:2
        bcf     OPTION_REG, 2     		; Prescaler Rate Select bit 2
        bcf     OPTION_REG, 1     		; Prescaler Rate Select bit 1
        bcf     OPTION_REG, 0     		; Prescaler Rate Select bit 0

        bcf    STATUS, 5         		; ---- Select Bank 0 -----




;***************************************************************
;interrupt on-change register
	bsf     STATUS,5
	
	movlw  	b'00011011'		;enable global interrupts in order for the individual pin to be configured(kalo switch
	movwf	IOC

	movlw	b'00000000'		;peripheral interrupt register; disable
	movwf 	PIE1			

	bcf    STATUS,5

	movlw	b'00001000'		;enable interrupt control register 
	movwf	INTCON
	

;******************************************************************
;MAIN PROGRAM
;*****************************************************************8
MAIN

              
        bsf     INTCON,7  ; enable global interrupts
	;	bsf		rfena     ; enable	transmitter
		call    BITCHECK
		
;*****************************************************************
;CHECK INPUT
;*****************************************************************

	
BITCHECK
	btfsc	nobit2,3 
	goto	TRANSMIT
	
	movfw	GPIO
	movwf	input	
	incf	nobit2,f
	movfw	nobit2
	movwf	nobit

	
	btfsc	nobit2,2
	goto	checkleft	;for bit number 4,5,6,7
	goto	checkright	;for bit number 1,2,3,8


checkleft

	btfsc	nobit2,1
	goto	rleft
	btfsc	nobit2,0
	goto	bit5
	goto	rright1
	return;
checkright
	btfsc	nobit2,3
	goto	rleft
	return;
rright1
	movlw	d'5'
	movwf	rtime
	return;
rright
	
	decf	rtime,f
	decfsz	nobit
	goto	rright
;	movwf	rtime
rotater
	rrf		input,f
	decfsz	rtime
	goto	rotater
	movfw	input	
	xorwf	store,w
	movwf	store
	goto    BITCHECK
	return;
bit5
	movfw	input
	xorwf	store,w
	movwf	store
	goto	BITCHECK
	return;
rleft

	movfw	nobit
	movwf	ltime
	decf	ltime
	decf	ltime
	decf	ltime
	decf	ltime	
	decf	ltime
	return
rotatel
	rlf		input,f

	decfsz	ltime
	goto	rotatel	
	movfw	input	
	xorwf	store,w
	movwf	store
	goto    BITCHECK	
    return;                                   
TRANSMIT
		bsf		GPIO,5
; send preamble (50% duty cycle)
Preamble					;send 16 bit
      movlw   d'16'
      movwf   BitCount          ; init number of preamble bits

PreL
        bsf     txd             ; ON
        movlw	1
		call    WaitxTE           ; delay
        bcf     txd             ; OFF
       	movlw	1
		call    WaitxTE             ; delay
        decfsz  BitCount,F      ; loop
        goto    PreL
            
; sync pause

TXloop      
                
       movlw d'10'
	   call    WaitxTE         ; Theader = 10 x Te
            
; send 72 bit pattern

        movlw   store            ; lsb first 
        movwf   FSR
            
TXNextByte
      movlw   D'8'
      movwf   BitCount

TXNextBit
		
        rrf     INDF,W           ; 8 bit rotate | rotate right f through carry
        rrf     INDF,F           ; Carry contain lsb
        BC      ONE				 ; branch on carry | goto ONE if bit is set
ZERO    					;wave pattern if the bit is zero        
        movlw   2               ; 
	    movwf   TimeHi          ;   +---+---+   +--
        movlw   1               ;   |       |   |
   		movwf   TimeLo          ;---+       +---+
        goto    Trasm_BIT       ;   |  2Te   Te |

ONE							;wave pattern if the bit is one
        movlw   1              	;              
        movwf   TimeHi          ;   +---+       +--
        movlw   2               ;   |   |       |
        movwf   TimeLo          ;---+   +---+---+
                                ;   | Te   2Te  |
	
Trasm_BIT

        bsf     txd             ; ON
        movf    TimeHi,W          
        call    WaitxTE
		
        bcf     txd             ; OFF
        movf    TimeLo,W          
        call    WaitxTE

       	decfsz  BitCount,F
        goto    TXNextBit       ; loop on bits

   
; guard time
        movlw   TGUARD
        call    WaitxTE

       org     0x3ff
       retlw    0x80

	
;----------------------------------------------------------------------
        end                         ; end of program directive
;----------------------------------------------------------------------