Yup. That's the one. That must be where I originally got it from then.=20

Dave

> -----Original Message-----
> From: pic microcontroller discussion list
> [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Welch, Ken
> Sent: 02 August 2002 23:48
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [PIC]: F877 I2C module
>=20
> its a tutorial on MicroChip web site
>=20
> http://www.microchip.com/download/lit/suppdoc/toots/i2c.pdf
>=20
>=20
>=20
> -----Original Message-----
> From: Dave [mailto:Dave@NTI-SOLUTIONS.ORG]
> Sent: Friday, August 02, 2002 2:02 AM
> To: PICLIST@MITVMA.MIT.EDU
> Subject: Re: [PIC]: F877 I2C module
>=20
>=20
> Hey,
>=20
> I have a PDF document of a microchip presentation entitled "I2C(tm)
> Master
> Mode Overview and Use of the PICmicro=AE MSSP I 2 C Interface" I found
> it
> was really useful when I was writing my I2C code.
>=20
> It's about 400k and I can't remember where I got it from so if
> anyone
> wants it I'd be happy to email it off list.
>=20
> Regards,
> David Stubbs
>=20
> > -----Original Message-----
> > From: pic microcontroller discussion list
> > [mailto:PICLIST@MITVMA.MIT.EDU] On Behalf Of Tony K=FCbek
> > Sent: 02 August 2002 12:04
> > To: PICLIST@MITVMA.MIT.EDU
> > Subject: Re: [PIC]: F877 I2C module
> >
> > Hi,
> >
> > Jinx wrote:
> > > Does anyone have simple, repeat simple, code to show
> > > setup and operation of said module to read / write bytes
> > > to an EEPROM ? Examples I've found so far are convoluted
> > > over-blown state machines for multi-device systems that are
> > > way OTT for my needs. So much use of collision and error
> >
> > Hmm... what I have are pretty simple, however as it is an general
> > routine intended to be used be used inside the isr one might call
> > them overblown. But it's easy to rip out or simplify by omitting
> > as desired. But in case you stand by your request that an state
> > machine
> > is out of the question I'll refrain from posting the complete code
> > unless
> > you perhaps have a second thought :)
> >
> > > routines I found it hard to pick out the basics. Normally I'd
> > > nut it out myself but I've read that some examples (MC in
> > > particular) aren't worth the screen they're printed on, so I'd
> > > rather not waste time on published code that doesn't work
> > >
> > > TIA
> >
> > Agreed, but mine is actually based on an m-chip example but
> polished
> > until
> > is actually have some uses :)
> > BTW it's two 'modules' one for the i2c master (isr) functions and
> > one
> > for the
> > eechip functions.
> >
> > State =3D 0 -> local i2c idle
> > State =3D 1-3 -> i2c read
> > State =3D 4-8 -> i2c write
> > Uses BuffBankFsr (defined to any fsrX ) to read from any memory
> > location
> > within an dedicated buffer bank (only low adress used) when
> writing.
> > Uses FSR0 for reding to any memory location when reading.
> >
> >
> > Here's the main i2c state machine handler ( all of it ):
> >
> >
> > ;
> >
> ********************************************************************
> > ***
> > ;
> > ;  I2C_INT_HANDLER - Handles read/writes to/from i2c bus devices
> > ;  Uses an state variable i2c_State to preserv state between calls
> > ;
> > I2C_INT_HANDLER
> >         GLOBAL  I2C_INT_HANDLER
> >         BCF     _i2c_timetick ; clear timeout detect bit
> >         MOVF    i2c_State,W,A
> >         TABLE_JUMP_ISR_GTO I2C_JumpWrite
> > I2C_JumpWrite   ; address were jump table branch occurs, this addr
> > also
> > used in fill
> >         ; jump to processing for each state             =3D i2cState
> > value
> > for each state
> >         GOTO    I2C_WrtStart            ; write start sequence
> > =3D  0
> >         GOTO    I2C_SendWrtAddr         ; write address, R/W=3D1
> > =3D  1
> >         GOTO    I2C_WrtAckTest          ; test ack,write data
> > =3D  2
> >         GOTO    I2C_WrtStop             ; do stop if done
> > =3D  3
> > I2C_JumpRead
> >         GOTO    I2C_ReadStart           ; read start sequence
> > =3D  4
> >         GOTO    I2C_SendReadAddr        ; read address, R/W=3D0
> > =3D  5
> >         GOTO    I2C_ReadAckTest         ; test acknowledge after
> > address
> > =3D  6
> >         GOTO    I2C_ReadData            ; read more data
> > =3D  7
> >         GOTO    I2C_ReadStop            ; generate stop sequence
> > =3D  8
> >
> > I2C_JumpEnd
> >         Fill (RETURN),  (I2C_JumpWrite-I2C_JumpEnd) + (
> > i2c_SizeMask*4 )
> > ;-----------------------------------------------------------------
> --
> > ---
> > ;   ********************* Write data to Slave
> > *********************
> > ;-----------------------------------------------------------------
> --
> > ---
> > ; Generate I2C bus start condition       [ I2C STATE -> 0 ]
> > I2C_WrtStart
> >         INCF    i2c_State,F,A           ; update I2C state
> variable
> >         BSF     SSPCON2,SEN,A           ; initiate I2C bus start
> > condition
> >         MOVLW   LOW(I2C_Buffer)         ; setup buffer pointer to
> > start
> > of i2c buffer
> >         MOVWF   i2c_write_ptr,A         ;
> >         RETURN                          ;
> >
> > ; Generate I2C address write (R/W=3D0)             [ I2C STATE -> 1
> ]
> > I2C_SendWrtAddr
> >         MOVF    i2c_temp_address,W,A     ; get 7-bit address
> >         INCF    i2c_State,F,A            ; update I2C state
> variable
> >         MOVWF   SSPBUF,A                 ; initiate I2C bus write
> > condition
> >         RETURN                           ;
> >
> > ; Test acknowledge after address and data write  [ I2C STATE -> 2
> ]
> > I2C_WrtAckTest
> >         BTFSS   SSPCON2,ACKSTAT,A        ; test for acknowledge
> from
> > slave
> >         GOTO    I2C_WrtData              ; go to write data module
> >         BSF     _i2c_ackerror            ; set acknowledge error
> >         CLRF    i2c_State,A              ; reset I2C state
> variable
> >         BSF     SSPCON2,PEN,A            ; initiate I2C bus stop
> > condition
> >         RETURN                           ;
> > ; Generate I2C write data condition
> > I2C_WrtData
> >         ; first check if write count is zero
> >         MOVF    i2c_write_count,F,A     ; reload
> >         BTFSC   STATUS,Z
> >         GOTO    I2C_no_error            ; no bytes to write
> >         MOVF    i2c_write_ptr,W,A        ; retrieve ptr address
> >         MOVWF   BuffBankFSR              ; initialize FSR for
> > indirect
> > access
> >         INCF    i2c_write_ptr,F,A        ; inc. pointer for next
> > byte
> >         MOVF    BuffBankINDF,W,A         ; retrieve byte into w
> >         DECFSZ  i2c_write_count,F,A      ; test if all done with
> > writes
> >         GOTO    I2C_send_byte            ; not end of string
> >         INCF    i2c_State,F,A            ; update I2C state
> variable
> > I2C_send_byte
> >         MOVWF   SSPBUF,A                ; initiate I2C bus write
> > condition
> >         RETURN                          ;
> >
> > ; Generate I2C bus stop condition                [ I2C STATE -> 3
> ]
> > I2C_WrtStop
> >         BTFSS   SSPCON2,ACKSTAT,A        ; test for acknowledge
> from
> > slave
> >         GOTO    I2C_no_error             ; bypass setting error
> flag
> >         BSF     _i2c_ackerror            ; set acknowledge error
> >         CLRF    i2c_State,A              ; reset I2C state
> variable
> >         GOTO    I2C_stop
> > I2C_no_error
> >         CLRF    i2c_State,A              ; reset I2C state
> variable
> > ( to
> > idle )
> >         BSF     _i2c_writedone           ; set write done flag
> > I2C_stop
> >         BSF     SSPCON2,PEN,A            ; initiate I2C bus stop
> > condition
> >         RETURN                           ;
> > ;-----------------------------------------------------------------
> --
> > ---
> > ;   ********************* Read data from Slave
> > *********************
> > ;-----------------------------------------------------------------
> --
> > ---
> > ; Generate I2C start condition                   [ I2C STATE -> 4
> ]
> > I2C_ReadStart
> >         INCF    i2c_State,f              ; update I2C state
> variable
> >         BSF     SSPCON2,SEN              ; initiate I2C bus start
> > condition
> >         RETURN                           ;
> >
> > ; Generate I2C address write (R/W=3D1)             [ I2C STATE -> 5
> ]
> > I2C_SendReadAddr
> >         MOVF    i2c_temp_address,W,A     ; get 7-bit address
> >         INCF    i2c_State,F,A            ; update I2C state
> variable
> >         MOVWF   SSPBUF,A                 ; initiate I2C bus write
> > condition
> >         RETURN                           ;
> > ; Test acknowledge after address write           [ I2C STATE -> 6
> ]
> > I2C_ReadAckTest
> >         BTFSS   SSPCON2,ACKSTAT,A        ; test for acknowledge
> from
> > slave
> >         GOTO    I2C_StartReadData        ; good ack, go issue bus
> > read
> >         BSF     _i2c_ackerror            ; set acknowledge error
> >         CLRF    i2c_State,A              ; reset I2C state
> variable
> >         BSF     SSPCON2,PEN,A            ; initiate I2C bus stop
> > condition
> >         RETURN                           ;
> > I2C_StartReadData
> >         BSF     SSPCON2,RCEN,            ; generate receive
> > condition
> >         INCF    i2c_State,F,A            ; update I2C state
> variable
> >         RETURN
> > ; Read slave I2C                                 [ I2C STATE -> 7
> ]
> > I2C_ReadData
> >         MOVF    i2c_read_ptrH,W,A        ; retrieve high ptr
> address
> >         MOVWF   FSR0H                    ; initialize FSR0 high
> reg
> > for
> > indirect access
> >         MOVF    i2c_read_ptrL,W,A        ; retrieve low ptr
> address
> >         MOVWF   FSR0L                    ; initialize FSR0 low reg
> > for
> > indirect access
> >         INCF    i2c_read_ptrL,F,A        ; inc. pointer for next
> > byte
> >         MOVFF   SSPBUF,INDF0             ; save recieved byte
> >         DECFSZ  i2c_read_count,F,A       ; test if all done with
> > reads
> >         GOTO    I2C_SendReadAck          ; not end of string so
> send
> > ACK
> >
> > ; End of data Send Not Acknowledge
> > I2C_SendReadNack
> >         INCF    i2c_State,F,A            ; update I2C state
> variable
> > (
> > nxt is stop )
> >         BSF     SSPCON2,ACKDT,A          ; acknowledge bit state
> to
> > send
> > (not ack)
> >         BSF     SSPCON2,ACKEN,A          ; initiate acknowledge
> > sequence
> >         RETURN
> >
> > ; Send Acknowledge
> > I2C_SendReadAck
> >         BCF     SSPCON2,ACKDT,A          ; acknowledge bit state
> to
> > send
> >         BSF     SSPCON2,ACKEN,A          ; initiate acknowledge
> > sequence
> > I2C_SendReadAck_Wait
> >         BTFSC   SSPCON2,ACKEN,A          ; ack cycle complete?
> >         GOTO    I2C_SendReadAck_Wait     ; no, so loop again
> >         NOP
> >         BCF     PIR1,SSPIF,A    ; clear SSP H/W flag for ack
> >         NOP
> >         BSF     SSPCON2,RCEN,A           ; generate receive
> > condition
> >         RETURN                           ;
> >
> > ; Generate I2C stop condition                    [ I2C STATE -> 8
> ]
> > I2C_ReadStop
> >         BSF     SSPCON2,PEN,A            ; initiate I2C bus stop
> > condition
> >         CLRF    i2c_State,A              ; reset I2C state
> variable
> >         BSF     _i2c_readdone            ; set read done flag
> >         RETURN
> >
> > --
> > http://www.piclist.com hint: The PICList is archived three
> different
> > ways.  See http://www.piclist.com/#archives for details.
> >
>=20
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.
>=20
> --
> http://www.piclist.com hint: The PICList is archived three different
> ways.  See http://www.piclist.com/#archives for details.
>=20

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