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'A Few Questions From A Newbie'
1998\11\05@100456 by ley, Alec

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I have 4 questions for all of you out there in PIC world.  Please
answer.

1. I have a snippet of code that has a line defineing the crystal as
.1843200.  The code is for a 16C84.  What would the actual value of the
crystal be?

2. Would there be any problems with migrating code from a 16C84 to a
16F84?

3. Does anyone have any information on "Networking" 2 or more PICs
together?

4. Could anyone post a code snippet that shows how to use the EEPROM
memory area in the 16F84?

Thanks alot for any help.

Alec Beardsley

1998\11\05@120809 by Peter L. Peres

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On Thu, 5 Nov 1998, Beardsley, Alec wrote:

> I have 4 questions for all of you out there in PIC world.  Please
> answer.
>
> 1. I have a snippet of code that has a line defineing the crystal as
> .1843200.  The code is for a 16C84.  What would the actual value of the
> crystal be?

1.8432 MHz This sounds weird but it is 3.57 MHz / 2 (NTSC color carrier).

Peter

1998\11\05@122205 by Michael Hagberg

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1.8432 is a standard crystal frequency. it's used in application where RS232
or any serial connection is used. this frequency allows integer division to
generate exact baud rates.

michael

You may leave the list at any time by writing "SIGNOFF PICLIST" in the
   body of a message to spam_OUTLISTSERVTakeThisOuTspamMITVMA.MIT.EDU.

{Original Message removed}

1998\11\05@123846 by Peter L. Peres

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On Thu, 5 Nov 1998, Michael Hagberg wrote:

> 1.8432 is a standard crystal frequency. it's used in application where RS232
> or any serial connection is used. this frequency allows integer division to
> generate exact baud rates.

This is of course correct. I goofed, it has nothing to do with 3.57.
Sorry.

I have a set of crystals rubber stamped 1.8432 and stenciled 3.57. Wonder
which one...

Peter

1998\11\05@172621 by Tony Nixon

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Beardsley, Alec wrote:
>
> 1. I have a snippet of code that has a line defineing the crystal as
> .1843200.  The code is for a 16C84.  What would the actual value of the
> crystal be?

Probably 1.8432MHz

> 2. Would there be any problems with migrating code from a 16C84 to a
> 16F84?

None at all, except one of the fuses works opposite (can't recall which
one) Plus you get more RAM to play with with the F84.

> 3. Does anyone have any information on "Networking" 2 or more PICs
> together?

Could be a pretty big ask here, try searching the net. There's bound to
be plenty of info.

> 4. Could anyone post a code snippet that shows how to use the EEPROM
> memory area in the 16F84?

Store data (0xFF) to EEPROM address 0x00h

movlw 0xFF
movwf EEdata    ; set data
clrf EEadr      ; set address
bsf status,rp0  ; ram page 1
bsf EECON1,WREN ; allow EEPROM writes
movlw 55h
movwf EECON2
movlw 0xAA
movwf EECON2
bsf EECON1,WR   ; start the write sequence

wait
 btfsc EECON1,WR   ; wait while write operation completes
 goto wait

bcf EECON1,WREN ; disable writes
bcf status,rp0  ; ram page 0

Read data from EEPROM address 0x20

movlw 0x20
movwf EEadr     ; set address
bsf status,rp0  ; ram page 1
bsf EECON1,RD   ; initiate read
bcf status,rp0  ; ram page 0
movf EEdata,w   ; EEPROM data is now in W Reg


--
Best regards

Tony

Multimedia 16F84 Beginners PIC Tools.

http://www.picnpoke.com
Email .....picnpokeKILLspamspam@spam@cdi.com.au

1998\11\05@193221 by Eric Smith

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"Peter L. Peres" <plpspamKILLspamACTCOM.CO.IL> wrote:
> 1.8432 MHz This sounds weird but it is 3.57 MHz / 2 (NTSC color carrier).

No, it isn't.  1.8432, 3.6864, and 18.432 MHz are all routinely used because
they conveniently divide down to common baud rates.  They have no
particularly good relationship to television scan rates or color carrier
frequencies (either NTSC or PAL).

1998\11\20@064519 by Eric Smith

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"Peter L. Peres" <.....plpKILLspamspam.....ACTCOM.CO.IL> wrote:
> 1.8432 MHz This sounds weird but it is 3.57 MHz / 2 (NTSC color carrier).

No, it isn't.  1.8432, 3.6864, and 18.432 MHz are all routinely used because
they conveniently divide down to common baud rates.  They have no
particularly good relationship to television scan rates or color carrier
frequencies (either NTSC or PAL).

1998\11\20@070830 by Tony Nixon

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picon face
Beardsley, Alec wrote:
>
> 1. I have a snippet of code that has a line defineing the crystal as
> .1843200.  The code is for a 16C84.  What would the actual value of the
> crystal be?

Probably 1.8432MHz

> 2. Would there be any problems with migrating code from a 16C84 to a
> 16F84?

None at all, except one of the fuses works opposite (can't recall which
one) Plus you get more RAM to play with with the F84.

> 3. Does anyone have any information on "Networking" 2 or more PICs
> together?

Could be a pretty big ask here, try searching the net. There's bound to
be plenty of info.

> 4. Could anyone post a code snippet that shows how to use the EEPROM
> memory area in the 16F84?

Store data (0xFF) to EEPROM address 0x00h

movlw 0xFF
movwf EEdata    ; set data
clrf EEadr      ; set address
bsf status,rp0  ; ram page 1
bsf EECON1,WREN ; allow EEPROM writes
movlw 55h
movwf EECON2
movlw 0xAA
movwf EECON2
bsf EECON1,WR   ; start the write sequence

wait
 btfsc EECON1,WR   ; wait while write operation completes
 goto wait

bcf EECON1,WREN ; disable writes
bcf status,rp0  ; ram page 0

Read data from EEPROM address 0x20

movlw 0x20
movwf EEadr     ; set address
bsf status,rp0  ; ram page 1
bsf EECON1,RD   ; initiate read
bcf status,rp0  ; ram page 0
movf EEdata,w   ; EEPROM data is now in W Reg


--
Best regards

Tony

Multimedia 16F84 Beginners PIC Tools.

http://www.picnpoke.com
Email EraseMEpicnpokespam_OUTspamTakeThisOuTcdi.com.au

1998\11\20@074041 by Peter L. Peres

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On Thu, 5 Nov 1998, Michael Hagberg wrote:

> 1.8432 is a standard crystal frequency. it's used in application where RS232
> or any serial connection is used. this frequency allows integer division to
> generate exact baud rates.

This is of course correct. I goofed, it has nothing to do with 3.57.
Sorry.

I have a set of crystals rubber stamped 1.8432 and stenciled 3.57. Wonder
which one...

Peter

1998\11\20@074044 by Michael Hagberg

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face
1.8432 is a standard crystal frequency. it's used in application where RS232
or any serial connection is used. this frequency allows integer division to
generate exact baud rates.

michael

You may leave the list at any time by writing "SIGNOFF PICLIST" in the
   body of a message to LISTSERVspamspam_OUTMITVMA.MIT.EDU.

{Original Message removed}

1998\11\20@074106 by Peter L. Peres

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On Thu, 5 Nov 1998, Beardsley, Alec wrote:

> I have 4 questions for all of you out there in PIC world.  Please
> answer.
>
> 1. I have a snippet of code that has a line defineing the crystal as
> .1843200.  The code is for a 16C84.  What would the actual value of the
> crystal be?

1.8432 MHz This sounds weird but it is 3.57 MHz / 2 (NTSC color carrier).

Peter

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