Referral to ULPWU/PLVD code per AN879??

[johnny]

Hello I've just recently joined and found this post after a lot of research because I am wanting to do the same. I am using the chip 16F690 and I want to detect low battery also. I would be using 5volts to power on the chip and would want to detect 3.7volts or any voltage as long as its lower than 5volts when the voltage has dropped and the led would be used as the output to indicate this or a multimeter showing the voltage if possible. I have Implemented the code that has been provided by 'jelliss00' in the MPLAB software to build but the program but isn't working. If any of you can give guidance to me on developing the program I would really appreciate.

[Demon]

It would help if you posted your entire code, which PBP version and assembler. A schematic of your circuit is always a good idea.

Robert

[johnny]

Hi sorry about the late reply I have added the schematic and included the programming below. The Led would turn on when the potentiometer has been adjusted and the voltage comes to 2.5volts as I would be using comparator to detect voltage. The software I am using is MPLAB IDE version 8.92. The program doesn't seem to work I would appreciate your help on this.

list p=16F690
include "p16F690.inc"
radix dec

;***** CONFIGURATION
; ext reset, no code protect, no watchdog, 4 MHz int clock
__CONFIG _MCLRE_ON & _CP_OFF & _WDT_OFF & _IOSCFS_OFF & _IntRC_OSC_RB4EN
; pin assignments
#define LED PORTC,3 ; indicator LED on RC3
constant nLED=3 ; (port bit 3)

;***** RC CALIBRATION
RCCAL CODE 0x3FF ; processor reset vector
res 1 ; holds internal RC cal value, as a movlw k
;***** RESET VECTOR ************************************************** ***
RESET CODE 0x000 ; effective reset vector
movwf OSCCAL ; apply internal RC factory calibration

;***** MAIN PROGRAM ************************************************** ***
;***** Initialisation
start
; configure ports
movlw ~(1<<nLED) ; configure LED pin (only) as an output
tris PORTC

; configure comparator 1
movlw 1<<C1PREF|1<<C1NREF|1<<C1POL|1<<C1ON
; +ref is C1IN+ (C1PREF = 1)
; -ref is C1IN- (C1NREF = 1)
; normal polarity (C1POL = 1)
; comparator on (C1ON = 1)
movwf CM1CON0 ; -> C1OUT = 1 if C1IN+ > C1IN-

;***** Main loop
main_loop
; display comparator output
btfsc CM1CON0,C1OUT ; if comparator output high
bsf LED ; turn on LED
btfss CM1CON0,C1OUT ; if comparator output low
bcf LED ; turn off LED
; repeat forever
goto main_loop

END

[Demon]

To start:

Labels end with colons.

Assembler must be delimitted with ASM.

Is this really PIC BASIC?

Robert

Edit: PORTC.3 <--- period, not comma