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Christophe
Joined: 10 May 2005
Posts: 323
Location: Belgium
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| Expression must evaluate to a constant |
 Posted: Thu Jun 01, 2006 1:53 am |
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Hello,
this is my keypad matrix scanning code :
in NS.h
| Code: | // Definiëer keyboard matrix: 9R x 8K
//Rijen
#define R1 PIN_C0
#define R2 PIN_C1
#define R3 PIN_B1
#define R4 PIN_B2
#define R5 PIN_B3
#define R6 PIN_B4
#define R7 PIN_B5
#define R8 PIN_B6
#define R9 PIN_B7
//Kolommen
#define K1 PIN_D0
#define K2 PIN_D1
#define K3 PIN_D2
#define K4 PIN_D3
#define K5 PIN_D4
#define K6 PIN_D5
#define K7 PIN_D6
#define K8 PIN_D7 |
in main loop:
| Code: | //******************************* READ MATRIX ********************************//
void Read_Matrix ()
{
ALLES_LOS = TRUE;
PRESSED = FALSE;
Output_low (R1);
delay_us (100);
temp = input_d (); // Lees de waarde van de poort
Output_float (R1);
if ( (buffer [0] & temp) != buffer [0] ) // er is gedrukt
PRESSED = TRUE;
buffer [0] = buffer [0] & temp; // Onthoud dat er ingedrukt is
if (temp != 255)
Alles_los = FALSE;
// RIJ 2
Output_low (R2);
delay_us(100);
temp = input_d();
Output_float(R2);
if ((buffer[1] & temp) != buffer[1])
Pressed = TRUE;
buffer[1] = buffer [1] & temp;
if (temp != 255)
Alles_los = FALSE;
// RIJ 3
Output_low(R3);
delay_us(100);
temp = input_d();
Output_float(R3);
if ((buffer[2] & temp) != buffer[2])
Pressed = TRUE;
buffer[2] = buffer [2] & temp;
if (temp != 255)
Alles_los = FALSE;
// RIJ 4
Output_low(R4);
delay_us(100);
temp = input_d();
Output_float(R4);
if ((buffer[3] & temp) != buffer[3])
Pressed = TRUE;
buffer[3] = buffer [3] & temp;
if (temp != 255)
Alles_los = FALSE;
// RIJ 5
Output_low(R5);
delay_us(100);
temp = input_d();
Output_float(R5);
if ((buffer[4] & temp) != buffer[4])
Pressed = TRUE;
buffer[4] = buffer [4] & temp;
if (temp != 255)
Alles_los = FALSE;
// RIJ 6
Output_low(R6);
delay_us(100);
temp = input_d();
Output_float(R6);
if ((buffer[5] & temp) != buffer[5])
Pressed = TRUE;
buffer[5] = buffer [5] & temp;
if (temp != 255)
Alles_los = FALSE;
// RIJ 7
Output_low(R7);
delay_us(100);
temp = input_d();
Output_float(R7);
if ((buffer[6] & temp) != buffer[6])
Pressed = TRUE;
buffer[6] = buffer [6] & temp;
if (temp != 255)
Alles_los = FALSE;
// RIJ 8
Output_low(R8);
delay_us(100);
temp = input_d();
Output_float(R8);
if ((buffer[7] & temp) != buffer[7])
Pressed = TRUE;
buffer[7] = buffer [7] & temp;
if (temp != 255)
Alles_los = FALSE;
// RIJ 9
Output_low(R9);
delay_us(100);
temp = input_d();
Output_float(R9);
if ((buffer[8] & temp) != buffer[8])
Pressed = TRUE;
buffer[8] = buffer [8] & temp;
if (temp != 255)
Alles_los = FALSE;
} |
Now this works fine, but you can see that there is many the same code used. So I want to that shorter. This is my idea:
Global const array:
| Code: | const char Scan [9] = { PIN_C0, PIN_C1, PIN_B1, PIN_B2, PIN_B3, PIN_B4, PIN_B5,
PIN_B6, PIN_B7 }; |
scanning routine:
| Code: | void Read_Matrix ()
{
int8 j;
ALLES_LOS = TRUE;
PRESSED = FALSE;
// RIJ per RIJ inscannen
for ( j = 0 ; j < 9 ; j++ )
{
output_low (Scan [j]);
delay_us (75);
Temp = input_d ();
output_float (Scan [j]);
if ( ( Buffer [j] & Temp ) != Buffer [j] ) // er is gedrukt
PRESSED = TRUE;
Buffer [j] = Buffer [j] & Temp;
if (temp != 255)
ALLES_LOS = FALSE;
}
} |
Now my compîler gives error Expression must evaluate to a constant; I was hoping you guys could give hints on this? |
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ckielstra
Joined: 18 Mar 2004
Posts: 3680
Location: The Netherlands
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Christophe
Joined: 10 May 2005
Posts: 323
Location: Belgium
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| Posted: Thu Jun 01, 2006 5:33 am |
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thanks,
that was exactly what I needed; thanks for sharing:
| Code: | void Read_Matrix ()
{
int8 j;
ALLES_LOS = TRUE;
PRESSED = FALSE;
// RIJ per RIJ inscannen
for ( j = 0 ; j < 9 ; j++ )
{
do_pin_io (Scan [j], 0);
delay_us (75);
Temp = input_d ();
do_pin_io (Scan [j], 2);
if ( ( Buffer [j] & Temp ) != Buffer [j] ) // er is gedrukt
PRESSED = TRUE;
Buffer [j] = Buffer [j] & Temp;
if (temp != 255)
ALLES_LOS = FALSE;
}
}
// do_pin_io() --
// This function will perform an i/o action on a CCS pin.
// The ccs_pin parameter must be a value defined in the .H
// file for your PIC, such as PIN_B0, PIN_C5, etc.
// The CCS pin value and state can be passed in variables.
// The action must be as follows:
// Action = 0: Set the specified pin = 0
// Action = 1: Set the specified pin = 1
// Action = 2: Read the specified pin and return
// its value (0 or 1).
// Any action value > 2 will be treated as 2. For actions
// 0 and 1, the return value has no meaning (but 0 is
// returned).
int8 do_pin_io(int8 ccs_pin, int8 action)
{
int8 io_port;
int8 bitmask;
int8 retval;
int8 const bitmask_table[] = {0x01,0x02,0x04,0x08,0x10,0x20,0x40,0x80};
retval = 0;
io_port = ccs_pin >> 3; // Get the i/o port address
bitmask = bitmask_table[ccs_pin & 7];
if(action < 2) // Is this an output action ?
{
*(io_port | 0x80) &= ~bitmask; // Set TRIS = output
if(action)
{
*io_port |= bitmask; // Set pin = 1
}
else
{
*io_port &= ~bitmask; // Set pin = 0
}
}
else // If not, we will read the pin (action = 2)
{
*(io_port | 0x80) |= bitmask; // Set TRIS = input
retval = !!(*io_port & bitmask); // Read pin (ret. 0 or 1)
}
return(retval); // This only has meaning if action = 2
} |
However, when I want to say output_float (SOME_PIN), how can I state that? |
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Ttelmah
Guest
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| Posted: Thu Jun 01, 2006 5:52 am |
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If you read a pin, it is 'floated'. Output_float, is really just a version of the input function, that doesn't actually return the value. So 'action=2', will do what you want.
Best Wishes |
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