Hello,
Can anyone help me here with the PULSIN command using PICBASIC PRO on a 16F84A pic? I'm not asking because I'm too lazy to read and learn but because I'm getting more and more muddled as each night passes by and have tried so many different things that I'm getting lost.
I just can't seem to get it working right if at all and it's really getting me mad now. I want it to count the pulses on two pins via tactile switches and light or extinguish up to 10 LEDs in 1 second increments. One TXT file has IF-THEN statements and another has the IF-THEN statements within a WHILE-WEND for the count up section at least. Haven't progressed past that as I want to get that part working first.
W1 VAR WORD '16bit vairable W1 W2 VAR WORD '16bit vairable W2 W3 VAR WORD '16bit vairable W3
DEFINE PULSIN_ MAX 1000
W1 = 0 'Zero W1 PULSIN PORTB.0,1,W1 W3 = W3 + (W1 * 10) 'Multiply W1 increment count by 10uS and add 'W1 to W3
W2 = 0 'Zero w2 PULSIN PORTB.0,1,W2 W3 = W3 - (W2 * 10) 'Multiply W2 increment count by 10uS and 'subtract W2 from W3
IF W3 >= what?? AND W3 < what?? THEN LED1
I read that on a 16F84A with a 4MHz crystal the pulse-width returned is in 10uS increments so with the 16 bit vairable it's:
65535
* 10uS = 655350uS or a little over 0.65 seconds
1,000,000 uS = 1 second 100,000 increments * 10uS = 1 second
However the statement: PAUSE (period)
Gives a delay in milliseconds and (period) is also 16 bits so PAUSE 1000 is a 1 second delay.
This confuses me and I am very confused. If both are 16 bits then surely PULSIN could count up to a little over a minute like PAUSE or is PAUSE not dependent on the clock speed like PULSIN is?
Another question is what to do with any unused pins. I read somewhere but I can't find it again to be sure that it's best to tie each unused pin through a resistor to V-. Is this correct?
In addition I wish to replace the tactile switches at some point and connect the pins to a crossover switch controlling a motor powered by a 12V (13.8) battery. I read in a previous post reply by John Popelish to Richard Swinfen.
****************** Richard Swinfen
The PIC, 2803 and relays are powered by a 7805 with recommended
> caps on both sides (1uf & .33uf) itself powered by a 1.2A 12v regulated
> supply. Another possibly relevant point is that the PIC determines
> zero-crossing using a dirty-but-working 10MOhm direct live feed to RB0. I'll
> check removing this doesn't fix it.