Bits, Bytes Words and Arrays

[HenrikOlsson]

Hi,
That is weird.... This code:

MR var word: H var byte
 
MR = 0
HSEROUT ["First, all zeros:",13]
HSEROUT ["MR = ", BIN16 MR,13,13]
 
MR=65535
HSEROUT ["Then, all ones:",13]
HSEROUT ["MR = ", BIN16 MR,13,13]

for H=0 to 15
    MR.0[H]=0  'reset bit H of MR
next H
HSEROUT ["Next, all zeros again:",13]
HSEROUT ["MR = ",BIN16 MR,13,13]
 
for H=0 to 15
  MR.0[H]=1 'set bit H of MR
next H
HSEROUT ["And finally, all ones:",13]
HSEROUT ["MR = ", BIN16 MR,13,13]
 
Pause 10
END

Produces the following result on the serial terminal:

First, all zeros:
MR = 0000000000000000
 
Then, all ones:
MR = 1111111111111111
 
Next, all zeros again:
MR = 0000000000000000
 
And finally, all ones:
MR = 1111111111111111

The FOR-NEXT loop is copy-pasted from your post above. How do you know it's not setting the bit? Do you have serial line to which you can send the data as above? Is there any chanse something else in the program is resetting/changing MR before you have chanse to see it? What version of PBP? (I'm using 2.60)

/Henrik.

[vilaprinyo]

Thanks,

I tried to run the isolated code and it works. :S
I'm sorry. I tested only the complete program before.

Sure the problem is in the code between. the weird is it works compiled with PicBasic and not when compiled with PicBasicPro.

I will check possible causes...

Thanks again.

Ricard.

[vilaprinyo]

Hello,

I have more information.

I started commenting all the lines between this code, resulting the same. MR value is 0.
Next, I continued commenting all the lines outside this code. Result the same. MR value is 0.
Finally, I decided to comment step by step my array variables.

After 2 o 3 arrays commented I get MR=65535.

I repeated this process commenting other variables randomly with the same result. After 2 o 3 steps MR=65535.

My code is about 8k over a Pic16F877. Very fair but fits.

My conclusion is PicBasicPro compiler needs more memory for variables than PicBasic.

The weird is why the compiler gives no errors...

Many thanks,

Ricard.

[wellyboot]

ok... I've built an 8x8x8 LED cube using 18F452, I have encountered a problem with my array

each of the 512 leds as 1 bit assigned to it from leddata array

0 = bottom corner
511 = the top corner of the cube


leddata VAR BYTE[64]
litled VAR WORD

litled = 511
leddata.0(lilted) = 1

the above 2 lines lights up an led half way down the cube (I think it would correspond to 255)

but if I write this:

leddata.0(511) = 1

the correct LED lights up at the top corner of the cube

Any ideas?

[Ioannis]

You have an error in the variable litled.

leddata.0(lilted) = 1

It appears as lilted.

Ioannis

[wellyboot]

awww that was an autocorrect on here, not in my code

changed litled to 'lit' still no change,

I've changed my code now to address each led using X,Y,Z
and it is working ok


xl = 7
zl = 7
yl = 7
GOSUB ledon

ledon:
ledonbyte = xl + (yl*8)
ledtemp = leddata[ledonbyte]
ledtemp.0(zl) = 1
leddata[ledonbyte] = ledtemp
RETURN

[HenrikOlsson]

Hi,
I had a similar issue a couple of years (5) ago. Like you I found that indexing using a constant works but indexing using a variable doesn't (for bits beyond 255). And you, just like me back then, didn't bother to check the manual...

7.6.4 Accessing Arrays as Multiple Variable-Types
It is possible for a single array to be declared with multiple names and for each name to be assigned a different variable type. Note that offsets for BITs are limited to a maximum value of 255.

So, I Think Melanies post where she indicates that using a WORD as the pointer for indexing bits in a BYTE Array really isn't correct.

Here's my thread.

/Henrik.

[wellyboot]

Thanks Henik

solved that one