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Hawk
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| Keyboard, keypad debouncing and more |
 Posted: Sun Jan 11, 2009 7:53 am |
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Hello.
I've removed some parts from Mark's source code so it can fit my needs.
There is just single click check and hold down part.
I want to learn on this example but some help is welcome.
My end goal is to do keyboard (3x4, 4x4 debouncing on this way:
A B C a b c 1, A B C a b c 1, A B C a b c 1 and so on.
One button should be able to switch between this 7 possibilities and if you hold this button for 3 seconds, last char should be remembered.
The same as on mobile phones keypad.
--------------------------------------------------
Before i implement the keyboard i want to understand how to make this with the buttons on the picdem board , so i started with Mark's code.
1.) How to switch this possibilities thru some IF loop ?
2.) The clockspeed is 4 MHZ not 10 ( as in example ) so timer should be reconfigured.
Thank you.
| Quote: | case 0:
if (Switch_State[1] == SWITCH_HELD) // hold for 3 secounds
printf(lcd_putc,"\fSW1 Click\nWhile SW2 Held");
else
if ( )
{
printf(lcd_putc,"\fSW1 Click");
//-------------------------------
printf("A\n\r");
//-------------------------------
}
break; |
| Code: |
// Note to check timer2 setup if you change this to make sure it ints every ms
#define clockspeed 4000000
#use delay(clock=clockspeed)
#define CLICK_TIME 200 // Maximum time to consider a press/release a click
#define SWITCH_READ_TIME 30 // Interval to read the switches in ms
#define NUM_SWITCHES 2 // Good for up to 8 switches without having to modify the variable types
// Different types of click events
enum SWITCH_STATES
{
SWITCH_IDLE,
SWITCH_DOWN,
SWITCH_HELD, // last char confirmation
SINGLE_CLICK,
};
int8 Miliseconds; // Our system timer
int8 Read_Switch_Timer = 0; // How often we read the switch inputs
int1 Read_Switch_Flag = FALSE; // Signal to read the switches
int16 Click_Timer[NUM_SWITCHES]; // Timeout value or in this case the double click time
enum SWITCH_STATES Switch_State[NUM_SWITCHES];
// Timer 2 is our system tick
#int_timer2
void timer2_isr(void)
{
if (Miliseconds < 0xFF)
Miliseconds++;
}
// Handles what happens when we release a switch
void Switch_Released(int8 number)
{
if (number < NUM_SWITCHES) // Make sure this is a valid switch
{
switch (Switch_State[number])
{
case SWITCH_DOWN: // Set the timer to the maximum time between a press and release to consider this a single click
Click_Timer[number] = CLICK_TIME;
Switch_State[number] = SINGLE_CLICK;
break;
case SWITCH_HELD: // Just set the timer to a small number so that it will fire as soon as we release the switch
Click_Timer[number] = 1; // Don't change the state here, the timers will take care of it
break;
case SINGLE_CLICK: // Set the timer for the maximum time we will wait for a double click
break;
default:
Click_Timer[number] = 0;
Switch_State[number] = SWITCH_IDLE;
break;
}
}
}
//---------------------------------
void Switch_Pressed(int8 number) // Handles what happens when we press a switch
{
if (number < NUM_SWITCHES) // Make sure this is a valid switch
{
if (Switch_State[number] == SWITCH_IDLE) // Set the state to down only if we haven't just processed a click
Switch_State[number] = SWITCH_DOWN;
}
}
void Switch_Read_Value(void) // Handles debouncing of the switches
{
static int8 last_read = 0xFF;
static int8 last_state = 0xFF;
static int8 debounce_count;
int8 result = 0xFF;
int8 i;
int8 changed;
if (!input(PIN_A4)) // Read the current result
bit_clear(result,0);
if (!input(PIN_B0))
bit_clear(result,1);
if (result != last_read) // See if it changed
{
// It did so debounce it
debounce_count = 5;
last_read = result;
}
else if (debounce_count) // We are debouncing
{
debounce_count--;
if (debounce_count == 0) // Done debouncing
{
changed = (result ^ last_state); // See if the state of the switch has changed
for(i=0;i<8;i++) // Determine what type of event occurred
{
if (bit_test(changed,i))
{
if (bit_test(result,i))
Switch_Released(i);
else
Switch_Pressed(i);
}
last_state = result; // Save the current state
}
}
}
}
//***************************************************************
void Single_Click_Event(int8 number) // ***** ONE CLICK *****
{
switch(number) // TO ADD MORE SWITCHES you need to add the cases
{
case 0:
if (Switch_State[1] == SWITCH_HELD) // hold for 3 secounds
printf(lcd_putc,"\fSW1 Click\nWhile SW2 Held");
else
if ( )
{
printf(lcd_putc,"\fSW1 Click");
//-------------------------------
printf("A\n\r");
//-------------------------------
}
break;
case 1:
if (Switch_State[0] == SWITCH_HELD)
printf(lcd_putc,"\fSW2 Click\nWhile SW1 Held");
else
printf(lcd_putc,"\fSW2 Click");
printf("D\n\r");
break;
default:
break;
}
}
void Switch_Timers(void) // ***** Handles all our switch timers *****
{
int8 i;
if (Read_Switch_Timer == 0)
Read_Switch_Timer--;
else
Read_Switch_Flag = TRUE;
for(i=0;i<NUM_SWITCHES;i++)
{
if (Click_Timer[i])
{
Click_Timer[i]--;
if (Click_Timer[i] == 0)
{
switch (Switch_State[i])
{
case SWITCH_DOWN:
Switch_State[i] = SWITCH_HELD;
break;
case SWITCH_HELD:
Switch_State[i] = SWITCH_IDLE;
break;
case SINGLE_CLICK:
Single_Click_Event(i);
Switch_State[i] = SWITCH_IDLE;
break;
default:
Switch_State[i] = SWITCH_IDLE;
break;
}
}
}
}
}
void Switch_Tasks(void) //***** Handles all our switch tasks *****
{
if (Read_Switch_Flag)
{
Switch_Read_Value();
Read_Switch_Timer = SWITCH_READ_TIME;
Read_Switch_Flag = FALSE;
}
}
//**** System counter *****
void System_Tick(void)
{
while (Miliseconds)
{
Switch_Timers();
Miliseconds--;
}
}
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PCM programmer
Joined: 06 Sep 2003
Posts: 21708
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| Posted: Mon Jan 12, 2009 12:07 am |
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Mark's code does not work with a 3x4 keypad. It's intended for individual
switches, where each switch is connected to a separate PIC pin.
You will need a different driver for a 3x4 keypad.
Here is a data sheet for Grayhill 3x4 keypads. They have switches
wired in a matrix and have a 7-pin header on the back:
http://embrace.grayhill.com/embrace/IMAGES/PDF/c-06-09.pdf |
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Hawk
Guest
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| Posted: Mon Jan 12, 2009 12:50 pm |
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Hi PCM Programmer,
and thank you for reply.
Yes i am aware that Mark's code is for individual switches only, but i was thinking that maybe it would be interesting to implement this kind of logic into keypad.
How would you make this what i described in first post ?
A B C a b c 1, A B C a b c 1, A B C a b c 1 and so on.
I now i have to use timers but i am not quite sure how will all this affect performance of the program, speed etc.
Anyway, where would you start ? |
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John P
Joined: 17 Sep 2003
Posts: 331
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| Posted: Mon Jan 12, 2009 5:06 pm |
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| Call me clueless, but what does "A B C a b c 1, A B C a b c 1, A B C a b c " mean? |
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dyeatman
Joined: 06 Sep 2003
Posts: 1934
Location: Norman, OK
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| Posted: Mon Jan 12, 2009 5:09 pm |
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| He wants it to cycle through the selections each time you push the button. First short push it displays A. the second short push it displays B etc. If you push and hold the button for three seconds it accepts that as the selection of the user. |
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Hawk
Guest
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| Posted: Sun Feb 01, 2009 6:05 am |
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What is better way to connect the keypad, regarding to functionality described in previous posts ?
This
ht://i44.tinypic*com/1szblz.jpg
or
ht://i40.tinypic*com/rbxyrp.jpg
I will try to use modified ccs keypad example and mark's state machine idea, to get what i need. Suggestions, examples ?
Thanx! |
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