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danielpepo
Joined: 12 Apr 2010
Posts: 5
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| Problems with bounce in code |
 Posted: Fri Apr 30, 2010 2:09 pm |
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I'm using this code to know if a wheel is turning right or left and to increment or decrement the times it turns and show it in a couple of 7segment displays.
When the wheel stops on one of the optical switches, after a few seconds it starts to increment or decrement even though I'm using a debounce code. Can anyone please help me? Thanks!
| Code: |
#include <16F88.H>
#fuses XT, NOWDT, PUT
#use delay(clock=4000000)
#byte port_b=6
int8 unid = 2;
int8 dece = 2;
int8 reta = 1;
int8 flag_b2 = 0;
int8 flag_b3 = 0;
int8 cont = 0;
// These are the "Bvar" variables.
int8 B2 = 0; // For the button on pin b2
int8 B3 = 0; // For the button on pin b3
#include <Button.c>
// Function parameters:
//
// button(pin, DownState, Delay, Rate, BVar, Action)
//
// Returns: The value of the Action variable (normally
// set = 1) is returned when the button is
// pressed. When the button isn't pressed,
// the opposite value is returned (normally 0).
//======================================
void main(void)
{
delay_ms(10);
while(1)
{ //check if button is pressed, if so, increment units or tens
if(button(PIN_B2, 1, 0, 0, B2, 1))
{
cont++;
if(cont==1&&flag_b2!=1)
flag_b2=1;
}
//the LED with the low transistor lights
output_high(pin_b7);
output_high(pin_b6); //units
output_a(dece);
output_low(pin_b6); //tens on
delay_us(reta);
if(button(PIN_B3, 1, 0, 0, B3, 1))
{
cont++;
if(cont==2)
flag_b3=1;
}
if(flag_b2==1&&flag_b3==1)
{
cont=0;
flag_b2=0;
flag_b3=0;
if(unid<10)
{
unid++;
}
if(unid==10)
{
dece++;
unid=0;
}
if(dece==10)
{
dece=0;
unid=0;
}
}
if(cont==2)
{cont=0;
if(unid==0&&dece!=0)
{unid=9;
dece--;
}
else if(unid==0&&dece==0)
unid=0;
else
unid--;
}
if(!input(pin_B4)) //second button to reset counter
{
dece=0;
unid=0;
cont=0;
}
//the LED with the low transistor lights
output_high(pin_b7);
output_high(pin_b6); //units on
output_a(unid);
output_low(pin_b7); //tens
delay_us(reta);
}
} |
This is the debounce code:
| Code: | // Description of function parameters:
// Pin:
// This must be a CCS-style pin number, such as PIN_B0.
// Downstate:
// This is the logic level of the button when it's pressed.
// For a circuit with a Normally-Open switch and a pull-up
// resistor, this parameter will be 0.
// Delay:
// This is the initial delay before auto-repeat begins.
// Example: A Delay value of 50 means a 500 ms auto-repeat
// delay.
// Rate:
// This is the auto-repeat interval.
// Example: A Rate value of 10 gives a 100 ms interval,
// which means an auto-repeat rate of 10 keys per second.
// Bvar:
// This an 8-bit variable that must be declared in the main
// program, and it must be initialized to zero. There must
// be a separate variable for each button that you use.
// Example: Declare the variable for pin B0 as int8 B0 = 0;
// See the demo program for more examples. Note that Bvar
// is a "reference variable" (it has a "&" in front of it).
// This is intentional. It's done so the button function
// can directly access the Bvar variable which is declared
// outside the function, without having to pass a pointer
// to it. This keeps the function interface simple.
//====================================
// Action:
// This is the value that's returned when the button is
// pressed. Normally you set this = 1.
// Return value:
// When the button is pressed, the value of the Action
// parameter will be returned. When the button is not
// pressed, the opposite value will be returned.
// Normally, you set the Action parameter = 1, and so
// if the button is pressed, the function will return 1.
// If it's not pressed, it will return 0. So you just
// poll the function every 10 ms in a loop, and check the
// return value with an if() statement. If it's non-zero
// then the button is pressed and you can take appropriate
// action.
//=====================================
// The following macro is used by the Button function.
#define read_bit_var(x) bit_test(*(int8 *)(x >> 3), x & 7)
//=====================================
int8 button(int16 pin, int8 downstate, int8 delay,
int8 rate, int8 &BVar, int8 action)
{
int8 pin_value;
// Read the button pin.
pin_value = read_bit_var(pin);
// Check if the button is pressed. It's pressed if the
// pin value is the same as the "downstate". If it's not
// pressed, then zero the Bvar and return "Not pressed".
if(pin_value != downstate)
{
Bvar = 0;
return(!action);
}
// The button is pressed. Check to see if it's a new
// keypress. We can tell if it's a new keypress by
// checking if BVar = 0. If so, load the counter with
// the initial auto-repeat delay and return "Pressed".
// (If the delay has been set to 0, then load a non-zero
// value to allow the function to operate properly).
if(Bvar == 0)
{
if(delay == 0)
Bvar = 255;
else
Bvar = delay;
return(action);
}
// Decrement the auto-repeat counter.
Bvar--;
// Check if we just counted down to 0. If so, then load
// the counter with the auto-repeat interval and return
// "Pressed". If the delay is set to 0 or 255, it means
// that auto-repeat is disabled, so fall through and
// return "Not Pressed".
if(BVar == 0)
{
BVar = rate;
if((delay != 0) && (delay != 255))
return(action);
}
// If the counter is positive, then it means an auto-repeat
// is still pending, so return "Not Pressed".
return(!action);
} |
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Fri Apr 30, 2010 2:15 pm |
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| Quote: | void main(void)
{
delay_ms(10);
while(1)
{ //check if button is pressed, if so, increment units or tens
.
.
.
}
|
The 10ms delay is supposed to be inside the button polling loop.
You have it above the loop. |
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danielpepo
Joined: 12 Apr 2010
Posts: 5
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| Posted: Sun May 02, 2010 1:59 pm |
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There's another thing about the code, when I set the delay for 10ms, it takes about 4 seconds for the display to multiplex. Any ideas what's wrong?
Thank you |
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