IC2 pic 18f452 program problems

[GrandPa]

Hi Darrel!

The SDA and SCL can be on almost any pin. Just specify them in the I2CWRITE statement.

I know you're right, but then what's is the purpose of having specific pins listed in the datasheet for SCL and SDA? (I'm using PIC184620)

Is there any difference between those pins and any others regarding I2C?


J-P

[Darrel Taylor]

The dedicated SCL/SDA pins are for the SSP (Synchronous Serial Port).
The SSP module can do SPI or I2C, in Master or Slave modes.

The I2CWRITE/I2CREAD are bit bang routines that don't use the Hardware SSP, so they can use almost any pin as SDA and SCL.

There aren't any PBP commands that use the SSP directly.
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[MrSafe]

thank you I have solved it.

I have another problem I have a loop set up to where it sends messages out until the user presses a key.

example:

while key != 15

gosub getkey

serout PORTD.0, T1200, [X]

wend

To clarify this program sends data the first time but then waits for a user to press a key(other than 15) before sending the data again when it should send the data until the user presses a key (15).

[Darrel Taylor]

If your getkey subroutine doesn't return if no keys are pressed, it'll do what you are describing.

But it's hard to say whats wrong without seeing the getkey subroutine.
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[MrSafe]

Heres the subroutine for get key

'---- Subroutine to Key from keypad ----
'
getkey:
;
key = 0
PortC = 0 ' all outputs pins low
TrisC = $f0 ' bottom 4 pins out, top 4 pins in
;
input PORTC
;
pause 250
;
PORTC = %11111110 ' row 1
;
if PORTC.4 = 0 then
key = 1
return
endif
;
if PORTC.5 = 0 then
key = 2
return
endif
;
if PORTC.6 = 0 then
key = 3
return
endif
;
if PORTC.7 = 0 then
key = 12
return
endif
;
PORTC = %11111101 ' row 2
;
if PORTC.4 = 0 then
key = 4
return
endif
;
if PORTC.5 = 0 then
key = 5
return
endif
;
if PORTC.6 = 0 then
key = 6
return
endif
;
if PORTC.7 = 0 then
key = 13
return
endif
;
PORTC = %11111011 ' row 3
;
if PORTC.4 = 0 then
key = 7
return
endif
;
if PORTC.5 = 0 then
key = 8
return
endif
;
if PORTC.6 = 0 then
key = 9
return
endif
;
if PORTC.7 = 0 then
key = 14
return
endif
;
PORTC = %11110111 ' row 4
;
if PORTC.4 = 0 then
key = 10
return
endif
;
if PORTC.5 = 0 then
key = 0
return
endif
;
if PORTC.6 = 0 then
key = 11
return
endif
;
if PORTC.7 = 0 then
key = 15
return
endif
;
goto getkey
return
;
gotkey:
key = (col * 4) + (ncd (row ^ $f))
'
return
'
end

[Darrel Taylor]

Comment out the goto getkey just before GotKey:

That will keep it from waiting for a key before proceeding.
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