SIMPLE question

[ngeronikolos]

I am happy to be a member of that forum!!!!

I have a SIMPLE question.
I need to look at the 10 pins (portb.0-portb.7,porta.0,porta.1) in a loop and find the first pin that set 1.I need the simplest code to check that ports.

Thanks
Nikos

[duncan303]

Hi Nikos

I too am happy to be a member of this forum!!!

You could alias each pin into a word variable.
Then simply check the value of the whole word

If w0 > 1 then
etc etc
endif

or

while w0 <> 0
wend

I guess there are lots of other ways but this came into my mind first.

Hope this Helps

Duncan

[ngeronikolos]

Good idea Duncan,

But I want to find exactly the pin that is 1.
When you say word(variable)that can have 10bits???

Nikos

[duncan303]

Hi Nikos

A word is indeed 16bits, there is a great post by Melanie in the FAQ section I think, which describes how to address bits bytes words and arrays,

but I think first it is worth taking the time to fully digest pages 21 to 24 of the PBP manual. Every minute taken will pay back in Spades. Settle back with a nice cool glass of retsina.... take your time.

Just in case you do search for other info: a nybble is 4 bits but PBP does not access these directly.

Cheers and good luck

Duncan

[duncan303]

Hi again,

I did not answer your question fully,

you can determine which bit in the word variable that has been set by its value.

if w0 = 8 this is the same as %0000000000001000

so if you aliased say portb.1 to bit <3> in the word then you would know that when w0 = 8 portb.1 = 1

etc etc

Duncan

Its many years since i had a glass of retsina.. but you know I can still smell it even now

[Acetronics2]

Hi, N'Geron

you can use:

For I = 0 to 7

IF PORTA.0[I] = 1 THEN Bail_out

NEXT I

For I = 0 to 1

IF PORTB.0[I] = 1 THEN Bail_out

NEXT I

In simple words, you add the value I to the "Base address" that is PORTA.0 ... same for PortB

You have it "officially written" in the 2.50 Manual, at th REPEAT --- UNTIL Command page !!!

Alain

Alain

[ngeronikolos]

Duncan,

What I was thinking...

portA PORTB
% 00000000 / 00001000

<0> PORTB.0 <1>PORTB.1 .... <8>PORTA.0
Let's say that this is my word that Contains PORTA+PORTB that I have to check.
The followings are correct???
----------------------------------------------
w0 var word
L var byte
H var byte

L = PORTB
H = PORTA
w0.LowByte = L
w0.HighByte = H

If w0 > 1 then
I WILL READ THE w0
endif

---------------------------------------------------

Thanks
Nikos

Retsina,Summer,Sea and Sun

[paul borgmeier]

Duncan,

What I was thinking...

portA PORTB
% 00000000 / 00001000

<0> PORTB.0 <1>PORTB.1 .... <8>PORTA.0
Let's say that this is my word that Contains PORTA+PORTB that I have to check.
The followings are correct???
----------------------------------------------
(w0 var word
L var byte
H var byte

L = PORTB
H = PORTA
w0.LowByte = L
w0.HighByte = H

If w0 > 1 then
I WILL READ THE w0
endif

---------------------------------------------------

Thanks
Nikos

Retsina,Summer,Sea and Sun

If that is what you want to do, you could use Darrel's trick with EXT

@PORTS = PORTA
PORTS VAR WORD EXT  ; PORTS = PORTB:PORTA

; in middle of program

if PORTS > 1 then ....

(Don' t forget to mask the unused bits of PORTA if they might not be 0)