GMS87C1102 Datasheet, PDF (65/80 Pages) Hynix Semiconductor – CMOS SINGLE-CHIP 8-BIT MICROCONTROLLER

HYUNDAI MicroElectronics
GMS87C1102 / GMS87C1202
22. POWER FAIL PROCESSOR
The GMS87C1202 has an on-chip power fail detection cir-
cuitry to immunize against power noise. A configuration
register, PFDR, can enable (if clear/programmed) or disa-
ble (if set) the Power-fail Detect circuitry. If V_DD falls be-
low 3.0~4.0V range for longer than 50 nS, the Power fail
situation may reset MCU according to PFR bit of PFDR.
As below PFDR register is not implemented on the in-cir-
cuit emulator, user can not experiment with it. Therefore,
after final development of user program, this function may
be experimented.
Note: Power fail processor function is not available on 3V
operation, because this function will detect power
fail all the time.
PFDR
Power Fail Detector Register
-
-
-
-
Reserved
-
PFDIS PFDM
PFS
ADDRESS : EFH
RESET VALUE : -----100
Power Fail Status
0 : Normal Operate
1 : This bit force to "1" when
Power fail was detected
Operation Mode
0 : Normal operation regardless
of power fail
1 : MCU will be reset during power fail
Disable Flag
0 : Power fail detection enable
1 : Power fail detection disable
Figure 22-1 Power Fail Detector Register
RESET VECTOR
PFS =1
YES
NO
RAM CLEAR
INITIALIZE RAM DATA
INITIALIZE ALL PORTS
INITIALIZE REGISTERS
Skip the
initial routine
FUNTION
EXECUTION
Figure 22-2 Example S/W of RESET by Power fail
Oct. 1999 ver 1.0
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