MCP1726T-ADJZEMF Microchip Technology, MCP1726T-ADJZEMF Datasheet - Page 38

• Manufacturer Part Number: MCP1726T-ADJZEMF
• Description: Regulator, Extended Industrial, HVSON, 8-Pin|
• Manufacturer: Microchip Technology

PIC12F683
4.2.3
The ultra low-power wake-up on GP0 allows a slow
falling voltage to generate an interrupt-on-change on
GP0 without excess current consumption. The mode is
selected by setting the ULPWUE bit (PCON<5>). This
enables a small current sink which can be used to
discharge a capacitor on GP0.
To use this feature, the GP0 pin is configured to output
‘1’ to charge the capacitor, interrupt-on-change for GP0
is enabled, and GP0 is configured as an input. The
ULPWUE bit is set to begin the discharge and a SLEEP
instruction is performed. When the voltage on GP0
drops below V
cause the device to wake-up. Depending on the state of
the GIE bit (INTCON<7>), the device will either jump to
the interrupt vector (0004h) or execute the next instruc-
tion when the interrupt event occurs. See Section 4.2.2
“Interrupt-on-Change” and Section 12.4.3 “GPIO
Interrupt” for more information.
This feature provides a low-power technique for period-
ically waking up the device from Sleep. The time-out is
dependent on the discharge time of the RC circuit on
GP0. See Example 4-2 for initializing the ultra low-
power wake-up module.
The series resistor provides over-current protection for
the capacitor and can allow for software calibration of
the time-out. See Figure 4-1. A timer can be used to
measure the charge time and discharge time of the
capacitor. The charge time can then be adjusted to
provide the desired interrupt delay. This technique will
compensate for the affects of temperature, voltage and
component accuracy. The ultra low-power wake-up
peripheral can also be configured as a simple
Programmable Low-voltage Detect or temperature
sensor.
DS41211A-page 36
ULTRA LOW-POWER WAKE-UP
IL
, an interrupt will be generated which will
Advance Information
EXAMPLE 4-2:
FIGURE 4-1:
BCF
BSF
MOVLW H’7’
MOVWF CMCON0
BSF
BCF
BCF
CALL
BSF
BSF
BSF
MOVLW B’10001000’
MOVWF INTCON
SLEEP
STATUS,RP0
GPIO,0
STATUS,RP0
ANSEL,0
TRISIO,0
CapDelay
PCON,ULPWUE
IOC,0
TRISIO,0
C1
R1
ULTRA LOW-POWER
WAKE-UP INITIALIZATION
ULTRA LOW-POWER
WAKE-UP CIRCUIT
 2003 Microchip Technology Inc.
;Bank 0
;Set GP0 data latch
;Turn off
; comparator
;Bank 1
;GP0 to digital I/O
;Output high to
; charge capacitor
;Enable ULP Wake-up
;Select GP0 IOC
;GP0 to input
;Enable interrupt
; and clear flag
;Wait for IOC
GP0
PIC12F683