CDP1879 데이터 시트보기 (PDF) - Intersil
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CDP1879 Datasheet PDF : 18 Pages
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CDP1879, CDP1879C-1
FREEZE
CIRCUIT
AM - PM
AND
HOUR LOGIC
CALENDAR
LOGIC
XTAL
OSCILLATOR
XTAL
PRESCALE
SECOND
MINUTE
HOUR
DAY
MONTH
PRESCALE CLOCK
SELECT SELECT
CLOCK OUT
INT
RESET
VDD
VSS
CLOCK AND
INT. LOGIC
CONTROL
REGISTER
INT. STATUS
REGISTER
8-BIT DATA BUS
COMPARATOR
SECOND
LATCH
MINUTE
LATCH
HOUR
LATCH
I/O
INTERFACE
DB0-DB7
A0
A1
A2
TPA
I-O MEM
TPB/WR
RD
ADDRESS DECODE
AND
CONTROL LOGIC
CS
POWER DOWN
FIGURE 1. REAL-TIME CLOCK FUNCTIONAL DIAGRAM
TABLE 1.
CONTROL REGISTER BIT ASSIGNMENT
Bit 1, 0
Frequency 00
Select 01
10
11
32768Hz
1.048576MHz
2.097152MHz
4.194304MHz
Bit 2
Start/Stop
1 = Start
0 = Stop
Bit 3
Counter/Latch Control
“0” = Write to Counter and disable alarm
“1” = Write to and enable alarm Clock Select
Bit 7, 6, 5, 4
0000 - disableµs
0001 - 488.2µs
0010 - 976.5µs
0011 - 1953.1µs
0100 - 3906.2µs
0101 - 7812.5µs
0110 - 15.625ms
0111 - 31.25ms
1000 - 62.5ms
1001 - 125ms
1010 - 250ms
1011 - 500ms
1100 - sec.
1101 - min.
1110 - hour
1111 - day
TABLE 2.
ADDRESSES
A2
A1
A0
Latch, Counter Seconds
0
1
0
Latch, Counter Minutes
0
1
1
Latch, Counter Hours
1
0
0
Counter, Day
1
0
1
Counter, Month
1
1
0
Control, Register
1
1
1
Status Register
1
1
1
MSB of Hours Counters (Bit 7) is an AM-PM Bit. 0 = AM; 1 = PM
Bit 6 of Hours Counter Controls 12/24 hr. 1 = 12 Hr: 0 = 24 Hr.
Status Register: Bit 7 MSB = Alarm
Interrupt Source: Bit 6 = Clock.
MSB of Month Counter (Bit 7) is a Leap Year Bit 0 = No, 1 = Yes.
4-106
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