need simple solution

[hemnath]

I have 4 buttons connected to pic 18F2520. which are configured as inputs. I'm using CCS c compiler

below is the routine i'm using now,

if((input(PIN_A1) == 0) && (input(PIN_A2) == 0) && (input(PIN_A3) == 0) && (input(PIN_A4) == 0))  // 0000
{
variable = 0;
}

if((input(PIN_A1) == 0) && (input(PIN_A2) == 0) && (input(PIN_A3) == 0) && (input(PIN_A4) == 1))		// 0001
{
variable = 1;
}

like this  ... goes upto


if((input(PIN_A1) == 1) && (input(PIN_A2) == 1) && (input(PIN_A3) == 1) && (input(PIN_A4) == 1))		// 1111
{
variable = 15;
}

The problem is, i have to type so many lines to check the input status and the program becomes very large. Is there any simple solution to read the input?

Please help. Thanks in advance

 

[jayanth.devarayanadurga]

#define to replace each button press?

if PORTA = xxxx0000

if PORTA = xxxx0001

...

#define alloff {input(PIN_A1) && input(PIN_A2) && input(PIN_A3) && input(PIN_A4)};

 

[hemnath]

i've found a better solution,

unsigned char variable[16] = {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15};

while(1)
{
a = (input_a() & 0b1111);
value = variable[a];
output_b(value);
}

Looks so simple now

Well any one know any other solution, please post. So that i can learn and it may help me.

 

[jayanth.devarayanadurga]

See my last post.

 

[betwixt]

If the pins are all on the same port (I'm not sure of CCS syntax):

if(port & 0x02) result |= 8;
if(port & 0x04) result |= 4;
if(port & 0x08) result |= 2;
if(port & 0x10) result |= 1;

Note that the result in the original code has it's bits reversed !

If they are in MSB -> LSB order the code is simpler:

result = (port & 0x1E) >> 1;

Brian.