On 18/04/2011 13:11, Olin Lathrop wrote:
> Josh Koffman wrote:
>> Funnily enough, there is an 18F part that does it. The 18F4550 and the
>> 18F4455 both do it. I had a discussion with one of the Microchip
>> Training guys about that, and he didn't realize there was an 18F part
>> that did it either. The part I don't get it is that you have to
>> program the chip to enable the secondary port...using the original
>> port.
> No, the dedicated programming port is always "live" for programming when =
you
> raise the Vpp line of the dedicated port, if you've enabled the port by
> tying a line high.  On those chips, I can't see any reason to ever use th=
e
> traditional PGC and PGD lines.
>

I just had a read of the 18F4550 datasheet - you have to program the=20
relevant config bit first to enable the dedicated port. This would=20
appear to mean that you have to use the legacy port first.
I thought it was like the PIC32 (or other higher end PICs) where you can=20
use any port to program, and the config bit selects the debug port only,=20
but apparently not.

--=20
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