A small defaut in this compilation : portx.pin = var.bit

[brico31]

for example, this syntax :

• the source syntax GCB : portc.2=var1.5 (var1 is a byte)

• the compiler result :
  bcf PORTC,2 => here is the little problem, in first one the bit is always cleared
  btfsc VAR1,5
  bsf PORTC,2

in first, the compiler, clear the bit.
I think that it would be necessary to pass by a temporary variable then copy the result in the portx

Have you a solution without modifying the compiler ?

thinks
best regards.

Brico31

[Chuck Hellebuyck]

More detail needed.
What Device?
What Compiler level are you using?

You could create your own logic.
if var1.5 = 1 then
PORTC.2 = 1
else
PORTC.2 = 0
end if

[brico31]

hello,
the compiler is the last version ;Program compiled by Great Cow BASIC (0.9 11/5/2014)
the devices are 16F887 or F676 ..
the problem exists sense i use GCB, (0.9 15/11/2009) compiler version.

of course, between two variables it is not a problem but for port pin it s a glitch !

ok for the logic test.

brico31

[Anobium]

Sorry, this is a limitation of GCB. It is the way GCBASIC addresses individual bits. On a PIC, it uses btfss, btfsc, bsf and bcf instructions, all of which require the individual bit to be hard coded. A workaround.

~~~~
'Prepare a bit mask with only the correct bit set
TempMask = 0
Set C On
Repeat var1
Rotate TempMask Left
End Repeat
'set port OR you can OR with port bit to set as this... portc = portc OR TempMask
portc = TempMask
wait 100 ms

[brico31]

ok for the limitation.
I shall by-pass when it will be necessary.

thank you.

[Chuck Hellebuyck]

If the PORTC, 2 bit is set and the Var1, 5 is set then the i/o pin will see a glitch that drives it to ground very quickly. I've seen this cause issues in previous designs with other BASIC compilers so why can't a 'btfss' be added to the routine to test it before clearing the bit?

btfss VAR1,5 <==== Why can't this be added?
bcf PORTC,2
btfsc VAR1,5
bsf PORTC,2