Guest
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
<Snip>
******************
John Popelish
<Snip>
The networked connections can complicate things, since they are all
antennas that can feed spikes to the PIC. I big no-no is having any
connections to the PIC go outside the supply rails, even briefly. The
specs for the PIC are damage specs, not malfunction specs. You might
try adding an additional 1 Mohm resistor between the 10 Mohm resistor
and PIC, with a 4.7 volt zener at the junction of the resistors ot the
0v rail. This will eliminate any positive input voltage above 4.7
volts, and will limit the negative current ot a few tenths of a volt
across 1 Mohm.
<snip>
******************
I take it that something like this circuit would have to be connected
to the PICs input pins. Can anyone advise on the best values for a
13.8 volt battery?
Any help greatly appreciated.
Thankyou,
Andrew.
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
<Snip>
******************
John Popelish
<Snip>
The networked connections can complicate things, since they are all
antennas that can feed spikes to the PIC. I big no-no is having any
connections to the PIC go outside the supply rails, even briefly. The
specs for the PIC are damage specs, not malfunction specs. You might
try adding an additional 1 Mohm resistor between the 10 Mohm resistor
and PIC, with a 4.7 volt zener at the junction of the resistors ot the
0v rail. This will eliminate any positive input voltage above 4.7
volts, and will limit the negative current ot a few tenths of a volt
across 1 Mohm.
<snip>
******************
I take it that something like this circuit would have to be connected
to the PICs input pins. Can anyone advise on the best values for a
13.8 volt battery?
Any help greatly appreciated.
Thankyou,
Andrew.