paris1

Hi I studied assembly language in college but its been a few years since ive seen it. Could anyone tell me if im on the right track, my syntax is wrong but i just want to know if i remember the principles correctly. The following code is intended to measure the duty cycle of three inputs from an accelerometer. I know its not going to be right but i just want to know if im starting from the very beginning. Thanks

START:
INPUT_1: CJNE P1.1, "1", INPUT_1;----------------//WAIT FOR LINE TO GO HIGH
SETB T1;-------------------------------//START TIMER
LOW: CJNE P1.1, 0, LOW--------------------- //WAIT FOR LINE TO GO LOW
MOV T1 @ R0----------------------- //MOVE VALUE ON TIMER TO ADDRESS
INC RO -----------------------------//INCREMENT R0 TO CHANGE ADDRESS

2: IF P1.2 = 1;---------------------------//SAME PROCESS FOR 2ND INPUT
EN T1
IF P1.2 = 1;
MOV T1 @ R0
INC RO

3: IF P1.3 = 1;-----------------------------//SAME PROCESS FOR 3RD INPUT
EN T1;
IF P1.3 = 1
MOV T1 @ R0
MOV RO, ?-------------------// RESET R0 TO POINT TO ORIGINAL ADDRESS

ericgibbs

hi,
I would test to see if the line is already high when I enter the routine.
example: the INPUT_1: CJNE P1.1, "1", INPUT_1;----------------//
may already be high, if its running asynchronously.
So IF HIGH wait for LOW, then Start Timer/counter on next HIGH going edge.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

paris1

Thanks, thats good advice. hopefully that sort of thing will come back to me

ericgibbs

hi,
I have just written a similar program 'snippet' for two 'accelerometer' inputs,
look a 'Atomsoft's recent posts regarding acc, it may help.

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/