em78p210n ELAN Microelectronics Corp, em78p210n Datasheet - Page 53

• Manufacturer Part Number: em78p210n
• Description: 8-bit Microcontroller With Otp Rom
• Manufacturer: ELAN Microelectronics Corp

Product Specification (V1.2) 04.22.2008
(This specification is subject to change without further notice)
6.10 Low Voltage Reset
The low voltage reset (LVR) is designed for unstable power situation, such as external
power noise interference or in EMS test condition.
When LVR is enabled, system supply voltage (Vdd) drops below Vdd reset level
(V
reset status. The system will remain at reset status until Vdd voltage rises above Vdd
release level. Refer to Figure 6-20.
LVR property is set at Code Option Word 0, Bits 10, 9. Detailed operation mode is as
follows:
Bits 10~9 (LVR1 ~ LVR0): Low Voltage Reset enable bits. If Vdd has a crossover at
Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
TYPE1 TYPE0 LVR1 LVR0 CLKS ENWDTB OSC2 OSC1 OSC0
Internal
Reset
RESET
Vdd
LVR1, LVR0
) and remains 10us, the system reset will occur and the system will keep on
11
10
01
00
Vdd reset level as Vdd changes, the system will be reset.
Vdd < Vreset not longer than 10us, the system still keeps on operating
Figure 6-20 LVR Waveform Situation
VDD Reset Level
<LVR Voltage drop
NA (Power-on Reset) (default)
2.5V
3.0V
4.0V
Bit 7
Word 0
Bit 6 Bit 5
VDD Release Level
8-Bit Microcontroller with OTP ROM
2.7V
3.2V
4.2V
>LVR Voltage drop
Bit 4 Bit 3 Bit 2
-
System reset occurs
18ms
EM78P210N
V
Protect
Bit 1
RESET
Bit 0
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