Error

[tekdavid]

i am using picbasic and this should work but it dont can any one tell me were my error is in program fornext

error fornext.bas,12: ':' or '=" expected (token 'var')
error fornext.bas,13: variable expected (token 'i')
error fornext.bas,17: next without maching for




12: i VAR byte
13: for i = 1 to 4
14: high 0
15: pause 1000
16: low 0
17: next i

[Melanie]

The clue is the common denominator for lines 12, 13 and 17... it doesn't like your variable.

I don't have PICBasic, only PICBasic Pro, however, whilst your code would be valid in PBP, in PBC I believe the variables are predefined... you must use them, although (and I stand to be corrected) you might be able to alias them... try this as a starter...

for B0 = 1 to 4
high 0
pause 1000
low 0
next B0

Consult the PBC manual for variables.

[bartman]

You do have to use the pre-assigned variables as mentioned here or use this at the beginning:

i symbol B0

to assign your own name to the variable.

Bart

[Dwayne]

Hello tekdavid,

TD>>12: i VAR byte
13: for i = 1 to 4
14: high 0
15: pause 1000
16: low 0
17: next i<<

I also question lines 14 and 16...

Usually it is a High Porta.0 or Low Porta.0 or
it may be High Portb.0 or Low portb.0

Either way, It might be good to assign a port to it.

Another problem... What do your lines BEFORE line 12 look like?
Sometimes the compiler may flag line 12, but the problem is actually
in line 10 or 11....

Dwayne

[Melanie]

I think it's the illegal (undeclared) variable 'i' in this case Dwayne...

High 0 and Low 0 are valid for addressing pin 0 of your PIC (note that which physical pin that pin 0 refers to is dependant of the PIC family - refer to the PICBasic manual for that).

[Dwayne]

Hello Melanie,

Melanie>>High 0 and Low 0 are valid for addressing pin 0 of your PIC (note that which physical pin that pin 0 refers to is dependant of the PIC family - refer to the PICBasic manual for that).<<

Gotcha...I wasn't sure which pic they were using...

I always seem to get myself into trouble if I don't spell it out <smile>.. Thus I kinda do things the "long Hand" way...GPIO.0, Porta.0, or whatever. Its kinda like those headers at the beginning of your file, If it is already defined for your chip, it can save *ME* a lot of time trying to figure out why my compiler is burping at me.

[Melanie]

Thus I kinda do things the "long Hand" way...GPIO.0, Porta.0, or whatever.

You really must try to avoid coding GPIO.0 or PortA.0 (or similar) in your programs... I'll tell you why... you have fifteen instances in a thousand lines of code where you refer to a particular pin... Firstly - just get ONE of those instances wrong and your code is screwed... but you'll never know it until that particular piece of code is executed. Secondly - you're laying out your PCB and you discover it's easier to place your components and lay your tracks if you swapped pins PortA.5 with PortB.6. You now spend half a day trying to find all the references to those pins in your program and worry about swapping them over.

There is a better way...

At the start of your program, right after you've done all your Config Fuse Defines, you have a section where each and every pin on your PIC is defined (aliased), and you ONLY use those aliases in your program... example - a snip out of a program that uses a PIC16F876...

	'
	'	Hardware Defines
	'	================
		'
		' 	LCD Display
		'	-----------
	Define LCD_DREG PORTC	' Port for LCD Data
	Define LCD_DBIT 4	' Use upper 4 bits of Port
	Define LCD_RSREG PORTC	' Port for RegisterSelect (RS) bit
	Define LCD_RSBIT 3	' Port Pin for RS bit
	Define LCD_EREG PORTC	' Port for Enable (E) bit
	Define LCD_EBIT 0	' Port Pin for E bit
	Define LCB_BITS 4	' Using 4-bit bus
	Define LCD_LINES 2	' Using 2 line Display
	Define LCD_COMMANDUS 2000
				' Command Delay (uS)
	Define LCD_DATAUS 50	' Data Delay (uS)
	LCDBackLight var PORTC.1
				' LCD Backlight PWM Pin
	LCDContrast var PORTC.2	' LCD Contrast PWM Pin
		'
		'	Sensor Inputs
		'	-------------
	PressIN var PortA.0	' Pressure Transducer Input
		'
		'	Button (Internet) Inputs
		'	------------------------
	ButtonDown var PortB.0	' SW2/Button DN
	ButtonUp var PortB.1	' SW1/Button UP
	ButtonSet var PortB.2	' SW3/Button SET/RST
	ButtonReserve var PortB.7
				' SW4/Exclusive CPU Access Button
		'
		'	System Outputs
		'	--------------
	GreenLED var PortA.1	' Green LED
	RedLED var PortA.2	' Red LED
	Beeper var PortA.3 	' Piezo Sounder
		'
		'	Communications I2C Bus
		'	----------------------
	SCL var PortA.4		' I2CLock
	SDA var PortA.5		' I2CData
		'
		'	Communications Inter-Processor (IP) Bus
		'	---------------------------------------
	IPAEnable var PortB.3	' IPENABLEA
	IPBEnable var PortB.6	' IPENABLEB
	IPClock var PortB.4	' IPCLOCK
	IPData var PortB.5	' IPDATA

Now, if I have to amend my program, and turn my Red LED on, rather than try to remember what pin my Red LED is connected to, I simply say...

High RedLED

and if I'm laying out my PCB and need to shuffle the pins about for convenience, there's just one section I need to look in to make changes globally in my program.

And better still, if I need to port my program to a different PIC, again, just one section reassigns all the pins.

Get in the habit of doing it this way - it will save you countless HOURS in the long term.