NS73M fm radio trasmitter

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  1. - 4th February 2009, 15:23 #1
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    Just a guess here but the NS73M is not 5V tolerant. The pins connected to the PIC should be level compensated to match the logic levels required for the NS73M or a 3V PIC should be used.

    I use the NS73M quite reliably but not in I2C mode and my routines are written in Swordfish so I can't really comment on your code. Sorry I can't help more.....

    Tom
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  2. - 5th February 2009, 02:41 #2
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    Tom, Thanks!

    Yeah, I have the NS73M on the end of a 3.3v regulator, and all but the LCD is on 3.3v.

    If I cant get I2C working, I guess I will go with the 3 wire... but was hoping not to have to use that extra pin...

    So goes life...

    Cheers!

    SmugWimp
  3. - 5th February 2009, 13:42 #3
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    Quote Originally Posted by Tom Estes View Post
    Just a guess here but the NS73M is not 5V tolerant. The pins connected to the PIC should be level compensated to match the logic levels required for the NS73M or a 3V PIC should be used.

    I use the NS73M quite reliably but not in I2C mode and my routines are written in Swordfish so I can't really comment on your code. Sorry I can't help more.....

    Tom
    If you want post the code.
    Thanks
    http://www.lesvoselectronic.com
    http://www.lesvoselectronics.com
  4. - 5th February 2009, 18:23 #4
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    Hello SmugWimp,
    16F877a has a bunch of analog stuff, some of it on portC, including C.1 and you must disable to send I²C as that data is digital. How about posting the whole code including the config statements. I would read sec. 4.3 of the data sheet, it explains about using portC in I²C communications and which pins to use. I do not know how much it affects the operation, but portC has Schmitt trigger input buffers. It may be because of that, it will only work on the pins Microchip has designated as I²C , it is certainly worth the effort to check. BTW, I do not see the jump label or a subroutine to be jumped to, must be in the unposted code . . . Have you attempted to try this on PortB ? No S. T. on the inputs there. here is a link of someone who got I²C to work : http://www.picbasic.co.uk/forum/showthread.php?t=5632 Looks like I2CWRITE is not a stand alone statement, looks like it requires all the registers to be set as the datasheet specifys . . . The manual gives the impression this is a bit banged solution, sort of looks like it is not.
    Last edited by Archangel; - 5th February 2009 at 19:24.
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  5. - 7th February 2009, 20:30 #5
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    Look at this thread it discusses using I²C w 3.3v . . . http://www.picbasic.co.uk/forum/show...9879#post69879 I noticed a comment re: not using schmitt trigger inputs . . .
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  6. - 8th February 2009, 03:36 #6
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    Joe,

    I appreciate all the help and suggestions.

    Here is my code, a schematic, and a photo of my setup.

    I have tried all kinds of things, and my underlying suspicion isnt that I am doing something wrong. I am just not finished with what is right.

    I have rewritten my code more similar to Boris' snippets, and his seems to work, heh. But mine still does not. Yet.


    My Configs are set as follows:

    __config _HS_OSC & _WDT_ON & _LVP_OFF & _CP_OFF & _WRT_OFF & _CPD_OFF & _BODEN_ON & _PWRTE_ON

    Code:
    '''''''''''''''''''''''''''''''''''''''
'''''''''''''''''''''''''''''''''''''''
''   NS73M Control Test Environment  ''
'''''''''''''''''''''''''''''''''''''''
'''''''''''''''''''''''''''''''''''''''
' We are using a PIC 16F877A
'
ADCON1=%00000111
Include "ModeDefs.Bas"
DEFINE OSC 4
TRISB=0
DEFINE LCD_DREG	PORTA	'Define PIC port used for LCD Data lines
DEFINE LCD_DBIT	0		'Define first pin of portb connected to LCD DB4
DEFINE LCD_RSREG PORTA	'Define PIC port used for RS line of LCD
DEFINE LCD_RSBIT 4		'Define Porta pin used for RS connection
DEFINE LCD_EREG	PORTB	'Define PIC prot used for E line of LCD
DEFINE LCD_EBIT	0		'Define PortB pin used for E connection
DEFINE LCD_BITS	4		'Define the 4 bit communication mode to LCD
DEFINE LCD_LINES 2		'Define using a 2 line LCD

NS_CK VAR PORTB.1	' I2C Clock Pin
NS_DA VAR PORTB.2	' I2C Data Pin
NS_CON VAR BYTE		' I2C Device (the NS73M) Control Address/ReadWrite Value
NS_REG VAR BYTE		' NS73M Register Address
NS_VAL VAR BYTE		' NS73M Register Value

NS_CON = %11001100	' Value of NS73M Address, with "Write" Bit

NS_REG=$0E:NS_VAL=$05:GOSUB WRITEDAMMIT ' Reset the chip right off...  They said to.
NS_REG=$01:NS_VAL=$B4:GOSUB WRITEDAMMIT ' Pilot On, Forced Subcarrier On
NS_REG=$02:NS_VAL=$07:GOSUB WRITEDAMMIT ' Full (2mw) Power, Unlock Detect On,
NS_REG=$03:NS_VAL=$58:GOSUB WRITEDAMMIT ' Lower Byte of Freq Address in Hex
NS_REG=$04:NS_VAL=$2A:GOSUB WRITEDAMMIT ' Upper Byte of Freq Address in Hex
NS_REG=$08:NS_VAL=$18:GOSUB WRITEDAMMIT ' CEX Band = 3 (For Now. Different Bands for Different Freq's)
NS_REG=$00:NS_VAL=$A1:GOSUB WRITEDAMMIT ' Xmtr RF On, 200mv input level for 100% Modulation
NS_REG=$0E:NS_VAL=$05:GOSUB WRITEDAMMIT ' Another Reset
NS_REG=$06:NS_VAL=$1E:GOSUB WRITEDAMMIT ' Set the Charge Pumps, whatever Charge Pumps are...
GOTO LCDSTUFF

WRITEDAMMIT:
I2CWRITE NS_DA,NS_CK,NS_CON,NS_REG,[NS_VAL] ' I2CWRITE Command. Supposed to work.
PAUSE 10 ' Don't know if this is necessary, but everyone writing to EEProms use it, I figured it couldn't hurt.
RETURN

LCDSTUFF:
LCDOUT $FE, 1
LCDOUT $FE, 2
PAUSE 500
LCDOUT $FE, $80
LCDOUT "  Are We" 
LCDOUT $FE, $C0
LCDOUT "Transmitting ??"
PAUSE 1000

THEEND:
END






    I know the chip in the schematic says "16F84AP". disregard that. In reality, it is a 16F877A; the pin connections are the same still.

    Any ideas would be a godsend. Thanks!

    Cheers!

    SmugWimp
    Last edited by SmugWimp; - 8th February 2009 at 03:53.
  7. - 8th February 2009, 08:47 #7
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    Have you pulled up the IIC pin #8
    If you do not believe in MAGIC, Consider how currency has value simply by printing it, and is then traded for real assets.
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  8. - 8th February 2009, 11:25 #8
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    It does not have a resistor on it, but "IIC" on the NS73M Board is tied to +3.3v, yes.

    Both the I2C Clock and Data lines are pulled to +3.3v with 1Kohm resistors. I have tried larger values, and it makes no difference.

    cheers!

    SmugWimp
    Last edited by SmugWimp; - 8th February 2009 at 11:27.
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