PIC 16F84A program help request.

Hello,

I'm in the process of learning to program the 16F84A PIC. I understand
that it's "old hat" but the PIC came with the programmer and they were
out of stock of the 16F628A PICs. I currently have an old version of
PicBasic Pro which can handle up to 16F84 PICs but seems to program
the 16F84A O.K. Once I'm familiar with the basics I'll probably
upgrade to the Oshon Pic Simulator IDE for the 16F628A.

I've decided to do a project for someone else to help me learn and so
far after much effort I'm gotten almost nowhere.

The project is a 10 LED bargraph indicator timed over 10 seconds. The
10 LEDs should light or extinguish at one second intervals according
to the pressing of Button#1 (Down) and Button#2 (Up).

I have written some code using the PULSIN command and IF-THEN
statements to light the LEDs but I can only get the first LED lit
before it has to return to the main loop and start again. Forever
going through the first If-THEN and no further.

How do I go about making this work? Does anyone have some sample code
I could adapt?

Any help is greatly appreciated here.

In addition though it's not shown in the schematics I assume that a
bypass cap is required across a PICs V+/V-. Correct?

Cheers,

Andrew.

 

[Anthony Fremont]

<Rubicon> wrote in message news:41b3e919.240583@news.netaccess.co.nz...

Hello,
snip
The project is a 10 LED bargraph indicator timed over 10 seconds. The
10 LEDs should light or extinguish at one second intervals according
to the pressing of Button#1 (Down) and Button#2 (Up).

I have written some code using the PULSIN command and IF-THEN
statements to light the LEDs but I can only get the first LED lit
before it has to return to the main loop and start again. Forever
going through the first If-THEN and no further.

Without a schematic and your source code, it will be quite difficult to
debug this from here. ;-) However, it sounds from your description
like the watch-dog timer could possibly be the problem. Make sure that
it is disabled.

How do I go about making this work? Does anyone have some sample code
I could adapt?

Any help is greatly appreciated here.

In addition though it's not shown in the schematics I assume that a
bypass cap is required across a PICs V+/V-. Correct?

It won't hurt.

 

Anthony,

Thanks for the reply.

The Pic is set up with a 4Mhz crystal with 33pF ceramic caps on
Pins#15 and 16. A 4K7 resistor from 5V+ goes to a tactile switch to V-
with a 100ohm resistor at the junction to PIN#4 MCLR. Pin#14 Vdd goes
to V+ with a 0.1uF ceramic cap to V-. RB0 and RB1 have 10K resistors
and tactile switches for positive pulses and RB2 is connected directly
to a small transducer. RB3/4/5/6/7 go to 330ohm resistors and LEDs to
V-. I haven't connected any more LEDs since I can't get past RB3/LED#1


The code is almost too embarrassing to post but in my defence it's
over twenty years since I last tried BASIC and COBOL at school. I
believe I'm getting better... I would hope so! Can't think of a way
past the IF_THENs or another way to do it.

Any advice, pointers appreciated.

Andrew.



''''''''''''''''''''''''''
' LED INDICATOR '
''''''''''''''''''''''''''
'Ten second, ten LED, one second increment/decrement incicator.
'If Button#1 depressed for over 10 seconds the excess is ignored.


DEFINE LOADER_USED 1


''''''''''''''''''''''''''
' HARDWARE STARTUP SETUP '
''''''''''''''''''''''''''

TRISA = %00000 'Set PORTA to all output
PORTA = 0 'PORTA (133) outputs off
TRISB = %00000011 'Set PORTB to all output but RB0 and RB1
PORTB = 0 'PORTB (134) outputs off
CLEAR 'Clear all vairables and buffers


''''''''''''''''''''''''
' INITIALIZE VAIRABLES '
''''''''''''''''''''''''
W0 VAR WORD '16 bit PULSIN vairable
W1 VAR WORD '16 bit PULSIN vairable
W2 VAR WORD '16 bit time vairable


''''''''''''''''
' STARTUP BEEP '
''''''''''''''''
GOSUB BEEP 'Sound a double beep on PORTB RB2


''''''''''''''''
' MAIN PROGRAM '
''''''''''''''''
LOOP1:

W0 = 0 'Zero W0
PULSIN 0,1,W0 'BUTTON#1 on RB0, measure high pw to W0
W2 = W2 + W0 'Add W0 to W2

W1 = 0 'Zero W1
PULSIN 1,1,W1 'BUTTON#2 on RB1, measure high pw to W1
W2 = W2 - W1 'Subtract W1 from W2

IF W2 >= 100 THEN LED1 'One second
IF W2 >= 200 THEN LED2
IF W2 >= 300 THEN LED3
IF W2 >= 400 THEN LED4
IF W2 >= 500 THEN LED5

'IF W2 >= 600 THEN LED6
'IF W2 >= 700 THEN LED7
'IF W2 >= 800 THEN LED8
'IF W2 >= 900 THEN LED9
'IF W2 >= 1000 THEN LED10 'Ten seconds
GOTO LOOP1


LED1:
PORTB.3 = 1 'Light LED1 - 1 sec
GOTO LOOP1

LED2:
PORTB.4 = 1 'Light LED2 - 2 sec
GOTO LOOP1

LED3:
PORTB.5 = 1 'Light LED3 - 3 sec
GOTO LOOP1

LED4:
PORTB.6 = 1 'Light LED4 - 4 sec
GOTO LOOP1

LED5:
PORTB.7 = 1 'Light LED5 - 5 sec
GOTO LOOP1


'LED10:
'PORTA??? 'Light LED10 - 10 sec
'W2 = 1000 'Set time to 10 seconds
'GOSUB BEEP 'Max time warning beep
'GOTO LOOP1


END


'''''''''''''''
' SUBROUTINES '
'''''''''''''''

BEEP:
SOUND PORTB.2, [120,10,60,10] 'Sound a double beep on PORTB RB2
RETURN











On Sun, 05 Dec 2004 10:57:30 GMT, "Anthony Fremont"
<spam@anywhere.com> wrote:

Rubicon> wrote in message news:41b3e919.240583@news.netaccess.co.nz...

Hello,
snip
The project is a 10 LED bargraph indicator timed over 10 seconds. The
10 LEDs should light or extinguish at one second intervals according
to the pressing of Button#1 (Down) and Button#2 (Up).

I have written some code using the PULSIN command and IF-THEN
statements to light the LEDs but I can only get the first LED lit
before it has to return to the main loop and start again. Forever
going through the first If-THEN and no further.

Without a schematic and your source code, it will be quite difficult to
debug this from here. ;-) However, it sounds from your description
like the watch-dog timer could possibly be the problem. Make sure that
it is disabled.

How do I go about making this work? Does anyone have some sample code
I could adapt?

Any help is greatly appreciated here.

In addition though it's not shown in the schematics I assume that a
bypass cap is required across a PICs V+/V-. Correct?

It won't hurt.