To make the 16F88 behave like the 16F84 you just have to disable the
analog functions.
In Assembly:
banksel cmcon
movlw 7
movwf cmcon
clrf ansel
banksel porta
In some high-level language:
CMCON = 7
ANSEL = 0
Mike
--- In piclist@picl..., Lez <lez.briddon@n...> wrote: >
> Built the 2 resistor serial link as shown in some pic basic PDF files, > and I have had no problem with the 16f84 (1k for
pic serout, 22k for serin) >
> re-compiled the program for a 16f88, plugged chip in, data from chip to > PC is ok but data from PC to chip is not being
seen by the PIC.
>
> I have led's on the lines, both led's glow when data is moving,
and
> typing on the PC keyboard flashed the LED, but the pic does nothing.
>
> Resistor change? more / less value ?
> Tried a wet finger it changes the led brightnes so I must be missing > something else about this port.
>
> Also tried a 648a and a 628a, both do same as f88.
>
> I am receiving data on a.0, sending data back to the pc on a.1
>
> I use a.2 as a 'ready to receive' led and that is fine.
> I use a.3 as a 'ready and powered' led and that is not coming on
at
> all(except on the f84)
>
> led's have a 1k resistor to gnd
> I thought the f88 and f84 were 'compatible' ?
>
> Quit and buy more 16f84's ?
Reply by Alan Marconett●August 9, 20052005-08-09
Hi Lez,
Had that happen to me on the '877.
ADCON0 = 0; /* A/D off */
ADCON1 = 6; /* all digital inputs */
HELPS! The A/D defaults ON. Another pair that got me:
CVRCON = 0; /* turn off compare modules */
CMCON = 7; /* 7 is power on reset, */
Although these are defaults, and can probably be ignored. I inadvertently
set CMCON = 0, thinking to turn 'em off, but that was wrong!
'88 has these registers, but I don't know off hand if these are the
same in
an '877.
Alan KM6VV
> -----Original Message-----
> From: piclist@picl... [mailto:piclist@picl...] On Behalf
> Of Lez
> Sent: Tuesday, August 09, 2005 12:53 PM
> To: piclist@picl...
> Subject: [piclist] 16f84 / 16f88 port a differences
> Built the 2 resistor serial link as shown in some pic basic PDF files,
> and I have had no problem with the 16f84 (1k for pic serout, 22k for
> serin)
>
> re-compiled the program for a 16f88, plugged chip in, data from chip to
> PC is ok but data from PC to chip is not being seen by the PIC.
>
> I have led's on the lines, both led's glow when data is moving,
and
> typing on the PC keyboard flashed the LED, but the pic does nothing.
>
> Resistor change? more / less value ?
> Tried a wet finger it changes the led brightnes so I must be missing
> something else about this port.
>
> Also tried a 648a and a 628a, both do same as f88.
>
> I am receiving data on a.0, sending data back to the pc on a.1
>
> I use a.2 as a 'ready to receive' led and that is fine.
> I use a.3 as a 'ready and powered' led and that is not coming on
at
> all(except on the f84)
>
> led's have a 1k resistor to gnd
> I thought the f88 and f84 were 'compatible' ?
>
> Quit and buy more 16f84's ?
Reply by smxcu●August 9, 20052005-08-09
--- In piclist@picl..., Lez <lez.briddon@n...> wrote: >
> Built the 2 resistor serial link as shown in some pic basic PDF files,
> and I have had no problem with the 16f84 (1k for pic serout, 22k for serin) >
> re-compiled the program for a 16f88, plugged chip in, data from chip to
> PC is ok but data from PC to chip is not being seen by the PIC.
>
> I have led's on the lines, both led's glow when data is moving,
and
> typing on the PC keyboard flashed the LED, but the pic does nothing.
>
> Resistor change? more / less value ?
> Tried a wet finger it changes the led brightnes so I must be missing
> something else about this port.
>
> Also tried a 648a and a 628a, both do same as f88.
>
> I am receiving data on a.0, sending data back to the pc on a.1
>
> I use a.2 as a 'ready to receive' led and that is fine.
> I use a.3 as a 'ready and powered' led and that is not coming on
at
> all(except on the f84)
>
> led's have a 1k resistor to gnd
> I thought the f88 and f84 were 'compatible' ?
>
> Quit and buy more 16f84's ?
The porta pins that you are using are also used by the A/D converter.
You need to ensure that they are configured as digital I/O and not
analog inputs. Check the data sheets.