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11 years ago.
Where is my error?
Hi! I need to read a membrane matrix keypad with my KL25Z this is my software where is the error?
prove2
#include "mbed.h"
#include "TextLCD.h"
BusIn colonne(PTC8,PTA5,PTA4);
BusOut righe(PTA12,PTD4,PTA2,PTA1);
TextLCD lcd(PTE5,PTE4,PTE3,PTE2,PTB11,PTB10);
char Keypad(void)
{
char key = 10;
righe.write(15);
righe.write(14);
switch(colonne)
{
case 3: key = 1; break;
case 5: key = 2; break;
case 6: key = 3; break;
}
righe.write(13);
switch(colonne)
{
case 3: key = 4; break;
case 5: key = 5; break;
case 6: key = 6; break;
}
righe.write(11);
switch(colonne)
{
case 3: key = 7; break;
case 5: key = 8; break;
case 6: key = 9; break;
}
righe.write(7);
switch(colonne)
{
case 3: key = '*';
case 5: key = 0;
case 6: key = '#';
}
return key;
}
int main(void)
{
char key;
lcd.cls();
while(1)
{
lcd.cls();
key = Keypad();
if(key != 10)
lcd.printf("%c\n\r",&key);
wait(0.2);
}
}
I've mounted 8.2Kohm pull up resistors on columns pins.
P.S.: colonne = columns, righe = rows
2 Answers
11 years ago.
You want to printf the returned key, which is a character.
lcd.printf("%c\n\r",&key);
What you actually print is the address of the 'key' variable.
Try
lcd.printf("%c\n\r", key);
You may also want to change the code in the keypad matrix scan function. In all cases except '*' and '#' you dont return printable characters but low ASCII codes (0, 1, 2 etc). These non-printable chars wont show on the LCD or serial terminal.
poster