I am stumped!!!

[aratti]

with the above setup why upon startup does my led blink?

Cannot answer without the schematic. Post how you wired your system, and I will try to give you an answer.

Al.

[tazntex]

I have a keypad, 3 rows, 4 columns, my rows are connected to PortB bits 1-3, the columns are connected to PortB bits 4-7. I set PortB.0 to 1 (high) feeding four 1n4148 diodes anode to PortB.0 cathodes to bit 4-7. When a button is pressed on the keypad it pulls whichever pin 4-7 low. I have OPTION_REG.6 = 0 to trigger on the falling edge.


Thanks

[tazntex]

keypad ohms out good, brand new actually, but as I mentioned before PortB.1-3 are my rows and 4-7 are my columns with the above code, pressing a button on the keypad does not pull any pin low.

[tazntex]

I changed TRISB = %11111110 to TRISB = %11110000 now pressing keypad the selected PORTB 4-7 pulls low to 2.2VDC, by the way PORTB.0 is connect first in series with a 330 ohm resistor, then to the four 1N4148's. I thought limiting the current to 15mA would be easier on the internal pull-ups.

[tazntex]

Thanks for the drawing, that is how this is connected, yes I am aware of "scanning the keypads" Bruce has been a great help, but I am just narrowing it down to pressing on button, pins 1-3 low, and pin 0 high just to see how interrupt's work. I am looking to use the interrupt to sleep all the time, detect when key is pressed, wake up, set PORTB.0, and 4-7 as inputs, bits 1-3 as out, pause about 50, then began scanning keypad something like this:

recycle:
@ Sleep
@ NOP
@ NOP
goto recycle

' my Interrupt handler
search:
PORTB = 0
TRISB = $f1
PAUSEUS 10
keypadscan:
FOR row = 1 TO 3
PORTB = 0
TRISB = (DCD row) ^ $fe
col = PORTB >> 4
IF col != $f THEN keypressed
NEXT row
GOTO recycle

Haven't got all this worked out yet, but thats another day

[tazntex]

I'm just stumped with the original code above why am I already in the interrupt when I power up, just to confirm that I changed the INT handler to:
'---[INT - interrupt handler]---------------------------------------------------
ToggleLED1:
TOGGLE LED
pause 50
@ INT_RETURN

and sure enough the led is flashing...

By the way, what program are you using to upload your schematic?

[tazntex]

Hmmm, came back here today to focus on the post here from Bruce but it seems to have vanished, or am I losing my mind? Maybe its both

Anyhow, it was mentioned that so to speak that I should take a snapshot of PortB, I am so lost. If on power up PortB.0 is high and pullups are enabled, on the rest of the pins: TRISB = %11111110 PortB = %00000001 then with my meter focusing on pins 4-7 shows 5VDC or logic HIGH, should I do this:

WHILE (portb >> 4) != 15
pause 20
wend
INTCON.0 = 0
return

or substitute 15 for a 0?

Seems it would be 15 but with that I apparently staying in my interrupt routine.

I've been experimenting with ON INTERRUPT and Darryl Taylor's Instant Interrupts:

DEFINE OSC 4
CMCON=%00000111
VRCON = 0
PAUSEus 10
TRISA = %00000110
TRISB = %11111110
PORTA = %00000000
PORTB = %00000001
OPTION_REG.7 = 0
OPTION_REG.6 = 0
INTCON = %00001000

led var portA.3
INCLUDE "DT_INTS-14.bas" ; Base Interrupt System
INCLUDE "ReEnterPBP.bas" ; Include if using PBP interrupts
ASM
INT_LIST macro ; IntSource, Label, Type, ResetFlag?
INT_Handler RBC_INT, _check, PBP, yes
endm
INT_CREATE

ENDASM
@ INT_ENABLE RBC_INT
PAUSE 50

cycle:
gosub readportb
HIGH led
pause 100
LOW led
pause 100
@ Sleep
@ Nop
@ Nop
goto cycle

readportb:
WHILE (portb >> 4) != 15
PAUSE 20
WEND
INTCON.0 = 0
return


check:
PAUSE 250
WHILE (portb >> 4) != 15
PAUSE 20
WEND
@ INT_RETURN


Any Suggestion, preferably in Crayola so its clear?

Thanks

[aratti]

I don't know how you want to connect your 3x4 keypad but the way you did explain is not going to work.

See the attached schematic. You have to put portB.1 to portB.3 (one at the time) to be an output and set it to low.
If you push one key of your keypad then the interrupt will detect the change (portB.4/7 going low) and will jump in the interrupt subroutine where you will decode the key, knowing which portB.1/3 was active low and which portB.4/7 was activated.

Al.