GMS81508B HYNIX [Hynix Semiconductor], GMS81508B Datasheet - Page 74

• Manufacturer Part Number: GMS81508B
• Description: HYUNDAI MICRO ELECTRONICS 8-BIT SINGLE-CHIP MICROCONTROLLERS
• Manufacturer: HYNIX [Hynix Semiconductor]

HYUNDAI MicroElectronics
21. POWER FAIL PROCESSOR
The GMS815xxB has an on-chip power fail detection cir-
cuitry to immunize against power noise. A configuration
register, PFDR, can enable or disable the power fail detect
circuitry. Whenever V
voltage for 100ns, the power fail situation may reset or
freeze MCU according to PFR bit of PFDR. Refer to “7.4
DC Electrical Characteristics” on page 13.
In the in-circuit emulator, power fail function is not imple-
mented and user can not experiment with it. Therefore, af-
ter final development of user program, this function may
be experimented or evaluated.
Note: User can select power fail voltage level according to
PFV bit of PFDR at the OTP(GMS815xxBT) but must select
the power fail voltage level to define PFD option of “Mask
Order & Verification Sheet” at the mask chip(GMS815xxB).
Because the power fail voltage level of mask chip
(GMS815xxB) is determined according to mask option re-
gardless of PFV bit of PFDR
DEC. 1999 Ver 1.04
PFDR
DD
falls close to or below power fail
7
Figure 21-1 Power Fail Voltage Detector Register
6
5
4
PFV
R/W
3
R/W
PFD
2
Note: If power fail voltage is selected to 3.0V on 3V oper-
ation, MCU is freezed at all the times.
R/W
PFR
1
Power FailFunction
Level Selection
Enable/Disable
R/W
PFS
0
Table 21-1 Power fail processor
Power Fail Status
0: Normal operate
1: Set to “1” if power fail is detected
Operation Mode
0: Normal operation regardless of power fail
1: MCU will be reset by power fail detection
Disable Flag
0: Power fail detection enable
1: Power fail detection disable
Power Fail Voltage Selection Flag
0: 2.4V
1: 3.0V
ADDRESS: 0F9
INITIAL VALUE: ---- 1100
by PFD flag
by PFV flag
H
OTP
GMS81508B/16B/24B
B
by mask option
by PFD flag
MASK
71