Holtek HT67F86A, Инструкции по применению

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HT67F86A Internal RTC Application Guidelines
AN0448E V1.00 4/7 January 16, 2017
TB1C Register
Bit 7 6 5 4 3 2 1 0
Name TB1ON — — — — TB12 TB11 TB10
R/W R/W — — — — R/W R/W R/W
POR 0 — — — — 0 0 0
Bit 7 TB1ON : Time Base 1 Enable Control
0: Disable
1: Enable
Bit 6~3 Unimplemented, read as “0”
Bit 2~0 TB12~TB10 : Time Base 1 time-out period selection
000: 2
8
/f
PSC
001: 2
9
/f
PSC
010: 2
10
/f
PSC
011: 2
11
/f
PSC
100: 2
12
/f
PSC
101: 2
13
/f
PSC
110: 2
14
/f
PSC
111: 2
15
/f
PSC
The f
PSC
is derived from the internal clock source f
LXT
/4.
Internal RTC Characteristics
Operating Voltage
The internal RTC operating voltage depends on the LXT oscillator which has a voltage
range of 2.2V~5.5V. Such applications are suitable for battery powered products which
require 2~3 batteries. Refer to the “Low Speed Crystal Oscillator Characteristics – LXT”
section in the datasheet or the following table for the related voltage characteristics.
Ta=25°C
Symbol Parameter
Test Condition
Min. Typ. Max. Unit
V
DD
Condition
f
LXT
Oscillator Frequency
2.2V~
5.5V
f
SYS
=f
LXT
=32.768kHz —
32.76
8
— kHz
Duty
Cycle
Duty Cycle — — 45 50 55 %
t
START
LXT Start-up Time — — — — 500 ms
R
NEG
Negative Resistance
Note
2.2V — 3×ESR — — Ω
Note: C1, C2 and R
P
are external components. C1=C2=15pF, R
P
=10M Ω , C
L
=7pF,
ESR=30k Ω .