Latched buttons

[peu]

I just wrote this program to start learning on interrupt, as expected... it didn't work

@ device pic12F675, intrc_osc_noclkout, wdt_on, mclr_off, protect_off

DEFINE OSC 4

trisio  =%00110000
ansel   =%00000000  
cmcon  =%00000111  'Comparators Off
intcon  =%10001100  'interrupts enable / tmr0 overflow / gpio change interrupt enable
OPTION_REG = %11010101    ' Set TMR0 configuration

but1    var gpio.4
but2    var gpio.5
led1    var gpio.1
led2    var gpio.2
ledwork var gpio.0

but1st  var bit
but2st  var bit

conta   var byte


on interrupt goto interrupcion

loop:

for conta=0 to 255 step 16  'working led rise routine
    pwm ledwork, conta, 10
        disable
        if but1st=1 then
            but1st=0
            high led1
        endif
        if but2st=1 then
            but2st=0
            high led2
        endif
        enable
    
next conta
high ledwork

for conta =0 to 100
    pause 10
next conta

low led1    'set status buttons leds off
low led2

for conta=0 to 255 step 16  'Fall routine
    pwm ledwork, 255-conta, 10
        disable
        if but1st=1 then
            but1st=0
            high led1
        endif
        if but2st=1 then
            but2st=0
            high led2
        endif
        enable
   
next conta
low ledwork

low led1   'set button status leds off
low led2

goto loop


disable
interrupcion:
    but1st=but1
    but2st=but2
    intcon  =%10001101
    resume
enable

Any help appreciated


Pablo

[peu]

I just changed the previous code so ledwork uses gpio.2 instead of gpio.3 because the payload of the program wasnt functioning properly (no idea why). Now it PWMs the led properly.

Im still reading the datasheet trying to figure out what I missed for the interrupt part


Pablo

[peu]

I fiddled with the intcon/option reg values and it seems to work, at least in the simulation

please tell me if you see someting blattantly wrong in the code:

@ device pic12F675, intrc_osc_noclkout, wdt_on, mclr_off, protect_off

DEFINE OSC 4

trisio  =%00110000
ansel   =%00000000  
cmcon  =%00000111  'Comparators Off
intcon  =%10101100  'interrupts enable 
OPTION_REG = %11010001    ' Set TMR0 configuration

but1    var gpio.4
but2    var gpio.5
led1    var gpio.1
led2    var gpio.2
ledwork var gpio.0

but1st  var bit
but2st  var bit

conta   var byte


on interrupt goto interrupcion

loop:

for conta=0 to 255 step 16  'working led rise routine
    pwm ledwork, conta, 10
;         disable
        if but1st=1 then
            but1st=0
            high led1
        endif
        if but2st=1 then
            but2st=0
            high led2
        endif
;         enable
    
next conta
high ledwork

for conta =0 to 100
    pause 10
next conta

low led1    'set status buttons leds off
low led2

for conta=0 to 255 step 16  'Fall routine
    pwm ledwork, 255-conta, 10
;         disable
        if but1st=1 then
            but1st=0
            high led1
        endif
        if but2st=1 then
            but2st=0
            high led2
        endif
;         enable
   
next conta
low ledwork

low led1   'set button status leds off
low led2

goto loop


disable
interrupcion:
    but1st=but1
    but2st=but2
    intcon  =%10001101
    resume
enable

Pablo

[J. Mark Wolf]

The attached PDF file is a circuit similar to one that was published in an old EDN Design Ideas. Originally it used a 74HCT374 and eight switches.

The advantage is that it latches and debounces the momentary switches. The KYBD_INT signal can be used for interrupting or polling. Once you've read the state of the switches, clear the latch and you're primed for the next keypress.

I've found it useful in the past, maybe you will to.