IF..THEN syntax

[scaenix]

Good day! I am a new user of PIC Basic and my version is PicBasic Pro 2.3 compiler. I am starting this thread because there is something that I cannot quite understand. There is a code in a book about robotics that I copied word for word into my editor, by the way I'm using MicroCode Studio 2003 for my editor, and somehow, when I tried to compile the program, there is an error message that says that the syntax is wrong. I'm including the code in here:

"if s1 > 225 then s1 = 225"

could anyone please help me or give me any idea why the compiler gives me an error message that the syntax is wrong? Thanks in advance!

[scaenix]

Please PM me if possible.. thanks!

[Archangel]

What does S1 represent?
you have a variable declared to represent s1?
examples:
s1 var byte
or
s1 var portB.1
or
symbol s1 = portb.1

[sayzer]

...

"if s1 > 225 then s1 = 225"...

There must be some other IF statements with missing THEN or ENDIF in the code.
One of those may be the cause of the error you get.

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

[Melanie]

PBP Version 2.3 is probably well over six years old (it's time MeLabs put a Date against the version releases on their website) and has many issues that have been fixed and improvements made over the subsequent years. You should seriously consider upgrading. Forum members here would be hard pressed to try to second-guess problems when you're using a product that old and you could spend many hours chasing a problem that has been long fixed and forgotten in the mists of time.

[scaenix]

I agree that the version I'm using is old but the program I tried to compile was also more or less 6 years old. anyway im pasting the whole program here for you to inspect. Thanks!


'Read Cds cell #1 on port b line 1
'Read Cds cell #2 on port b line 7
v1 var byte 'Variable v1 holds Cds #1 information
v2 var byte 'Variable v2 holds Cds #2 information
v3 var byte 'Variable for calculation
s1 var byte 'Variable s1 holds servomotor #1 pulse width info
s2 VAR word 'variable for random function
rv var byte 'variable rv holds the range value
s1 = 150 'initialize steering servomotor facing forward
rv = 10 'Adjust as needed for operation
ct var byte 'counter


start:
pot portb.2,255,v1
pot portb.3,255,v2

'Check bumper switch "Did I hit something?"
if porta.0 = 0 then avoid 'Hit obstacle go into avoid mode
'Is it sleepy time?
if v1 <= 230 then skp 'Is it dark enough to sleep?
if v2 > 230 then slp 'Yes

'Is it too bright to see?
skp:
if v1 >= 12 then skip2
if v2 < 12 then avoid

'Which way do I go?
skip2:
if v1 = v2 then straight
if v1 > v2 then greater
if v1 < v2 then lesser

straight:
pulsout portb.6, s1
pulsout portb.7, 157
goto start

greater:
v3 = v1 - v2
if v3 > rv then right
goto straight

lesser:
v3 = v2 - v1
if v3 > rv then left
goto straight

right:
s1 = s1 + 1
if s1 > 225 then s1 = 225
pulsout portb.6, s1
pulsout portb.7, 165
goto start
left:
s1 = s1 - 1
if s1 < 65 then s1 = 65
pulsout portb.6, s1
pulsout portb.7, 165
goto start

slp:
pulsout portb.6, s1
pulsout portb.7, 167
goto start

avoid:
random s2
s1 = s2 / 256
if s1 < 65 then s1 = 65
if s1 > 225 then s1 = 225
for ct = 1 to 125
pulsout portb.6, s1
pulsout portb.7, 177
pause 18
next ct

s1 = 150

goto start

[Darrel Taylor]

I just compiled it here for a 16F877. PBP 2.46

No errors.
<br>

[scaenix]

I just compiled it here for a 16F877. PBP 2.46

No errors.
<br>

I'm compiling it for a 16F84 with PBP 2.3

That's the only version I have because I can't afford to buy or upgrade.. I hope you understand :-)

[scaenix]

'Read Cds cell #1 on port b line 1
'Read Cds cell #2 on port b line 7
v1 var byte 'Variable v1 holds Cds #1 information
v2 var byte 'Variable v2 holds Cds #2 information
v3 var byte 'Variable for calculation
s1 var byte 'Variable s1 holds servomotor #1 pulse width info
s2 VAR word 'variable for random function
rv var byte 'variable rv holds the range value
s1 = 150 'initialize steering servomotor facing forward
rv = 10 'Adjust as needed for operation
ct var byte 'counter


start:
pot portb.2,255,v1
pot portb.3,255,v2

'Check bumper switch "Did I hit something?"
if porta.0 = 0 then avoid 'Hit obstacle go into avoid mode
'Is it sleepy time?
if v1 <= 230 then skp 'Is it dark enough to sleep?
if v2 > 230 then slp 'Yes

'Is it too bright to see?
skp:
if v1 >= 12 then skip2
if v2 < 12 then avoid

'Which way do I go?
skip2:
if v1 = v2 then straight
if v1 > v2 then greater
if v1 < v2 then lesser

straight:
pulsout portb.6, s1
pulsout portb.7, 157
goto start

greater:
v3 = v1 - v2
if v3 > rv then right
goto straight

lesser:
v3 = v2 - v1
if v3 > rv then left
goto straight

right:
s1 = s1 + 1
if s1 > 225 then s1 = 225
pulsout portb.6, s1
pulsout portb.7, 165
goto start
left:
s1 = s1 - 1
if s1 < 65 then s1 = 65
pulsout portb.6, s1
pulsout portb.7, 165
goto start

slp:
pulsout portb.6, s1
pulsout portb.7, 167
goto start

avoid:
random s2
s1 = s2 / 256
if s1 < 65 then s1 = 65
if s1 > 225 then s1 = 225
for ct = 1 to 125
pulsout portb.6, s1
pulsout portb.7, 177
pause 18
next ct

s1 = 150

goto start

I've quoted the code I've posted in one of the previous replies. the program is supposed to make the servomotor #1, which is connected to RB7 stop when in total darkness. I'm confused why the motor still continues on turning even if it is supposed to stop. Please anyone enlighten me on this. Thanks very much!

[mister_e]

I didn't read the whole thing but here's one fast suggestion for you.

Pulsout have to return the pin to it's previous state right? but nowhere the initial state have been set. When you turn on a PIC, the state of all pin is hard to predict. add those lines at the top of your code.

PORTB=0    ' Clear all PORTB pin
TRISB=0     ' Set all PORTB pins to output

if it doesn't work, you could still place a LOW PORTB.7 after each PULSOUT.

[scaenix]

PBP is great and easy to get along with. I'm saving to purchase an upgrade. Talking about what we've just discussed in the previous posts would certainly be worth another topic, say about piracy and intellectual rights? But then again, that is a very broad topic.
Huhum..let's move on..if anyone wants to start that topic somewhere then I suggest you request that in the forum. As for me, I've created another thread about inputting a mic into the 16f84.

[malc-c]

The issue of pirate copies will never go away. In an ideal world there would be no murders, break-ins, car jacking, robberies, hacking or bootlegging etc... but we don't live in an ideal world.

Someone mentioned cost... I've seen $10 applications pirated and placed up on the net for download, so its not the fact that a genuine copy cost so much. It seems that the low life that pirate these applictions do it just for fun or kudos.

In the example of reading a book rather than buying it, thats a bad example as you are still causing finacial hardship to both the author, publisher and retailer as its a lost sale. I mean you would hardly go out and buy the book for yourself if you had read your friends copy from cover to cover.

[Melanie]

I agree with most that you say with the exception of the book example.

If I buy a book (or CD or DVD or whatever), I'll probably read it and like with most people it is then destined to spend the rest of it's life abandoned on the shelf. You can come along and borrow the book, read it and return it to me. I can sell that book or give it away to someone else. But at any instance in time, only ONE COPY exists, but more than one person can enjoy the book, certainly not just the person who originally bought it. After all, all your school textbooks have probably been read many times before you and long after you have finished with them. Libraries would not exist where a single copy can be borrowed for the enjoyment of many. The objection is where someone COPIES the original work without recompensing the author/publisher.

[sayzer]

Another point of view is from me.

For US$10, I buy a pirate copy of a US$900 software.
I do the job and earn US$2,500.
Then I go to the shop and buy the original version at US$900.
Me = happy, software maker=happy, customer=happy

This is the way for me to buy the original version.

Who can call me a pirate software user?


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

[keithdoxey]

Another point of view is from me.

For US$10, I buy a pirate copy of a US$900 software.
I do the job and earn US$2,500.
Then I go to the shop and buy the original version at US$900.
Me = happy, software maker=happy, customer=happy

This is the way for me to buy the original version.

Who can call me a pirate software user?

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

At the point of doing the actual job you were a pirate user but having bought the software I suppose that legitimises it.

I have done similar with a disney film. Saw it at the movies, got a downloaded copy for the kids to watch (VCD) and then when the DVD came out I bought it so I dont feel that I have cheated Disney out of anything.

Having said that, we went to the Cinema a couple of weeks ago to see Night at the Museum. Good family film, current release. Last week I was talking to someone who said they hadnt seen it yet because they lent THEIR DVD to someone THREE WEEKS AGO before it was even on cinema release here.

I very much doubt that they have any intention of getting a genuine DVD once it is released and that is true of many users of Pirate Software