Post by thread:A Few Questions From A Newbie

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

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

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_OUTLISTSERVTakeThisOuTMITVMA.MIT.EDU. {Original Message removed}

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

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 .....picnpokeKILLspam@spam@cdi.com.au

"Peter L. Peres" <plpKILLspamACTCOM.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).

"Peter L. Peres" <.....plpKILLspam.....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).

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 LISTSERVspam_OUTMITVMA.MIT.EDU. {Original Message removed}