Reconfiguring buffered ports on the fly possible?

[kster59]

I have many times wanted to use buffered ports (fast deterministic data output) at one time and unbuffered ports at another.

Is it possible for me to call in sequence:
mybufferedportapplication();
myunbufferedportapp();

?

If so, what is the syntax in XC? It appears ports are assigned at the beginning of the code and can never be changed.

[mculibrk]

True.

The xs1.h has some useful functions to set port drive "type" (in, out, drive low, drive high...) but nothing about the "buffering".

You could use few "asm in-lines" for that - to set TW (transfer width) and buffered/unbuffered flags on the port resource.

Something like

Code: Select all

#define SETPORTBUFFERED(p, bits)     \
asm("\
setc res[%0], 0x200f  \n \
settw res[%0], %1   \n        \
" : : "r"(p), "r"(bits) );

#define SETPORTUNBUFFERED(p)   asm("setc res[%r], 0x2007" ::"r"(p));

but I'm not sure if it's necessary to stop/clear port before and re-start it later.

There are port transfer width and sift count parameters which which I'm not sure about the usage.
I suppose the "shift bits" should be equal to the port bits (or what??) and the transfer width to the actual "chunk" you which to put/get from the port buffer (shift register).

I'm also very intrigued about the 16-bit transfter - port:16 - which is not supported?!?!?! any idea why?

regards,
mculibrk

[Berni]

Oh thanks i remember having that problem before.