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參數(shù)資料
| 型號： | DS14285N |
| 廠商： | MAXIM INTEGRATED PRODUCTS INC |
| 元件分類： | Timer or RTC |
| 英文描述： | 1 TIMER(S), REAL TIME CLOCK, PDIP24 |
| 封裝： | 0.600 INCH, DIP-24 |
| 文件頁數(shù)： | 7/26頁 |
| 文件大?。?/td> | 515K |
| 代理商： | DS14285N |
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DS14285/DS14287
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Table 2. Periodic Interrupt Rate and Square-Wave Output Frequency
SELECT BITS REGISTER A
RS3
RS2
RS1
RS0
tPI PERIODIC
INTERRUPT RATE
SQW OUTPUT
FREQUENCY
0
None
0
1
3.90625ms
256Hz
0
1
0
7.8125ms
128Hz
0
1
122.070
s
8.192kHz
0
1
0
244.141
s
4.096kHz
0
1
0
1
488.281
s
2.048kHz
0
1
0
976.5625
s
1.024kHz
0
1
1.953125ms
512Hz
1
0
3.90625ms
256Hz
1
0
1
7.8125ms
128Hz
1
0
1
0
15.625ms
64Hz
1
0
1
31.25ms
32Hz
1
0
62.5ms
16Hz
1
0
1
125ms
8Hz
1
0
250ms
4Hz
1
500ms
2Hz
UPDATE CYCLE
The DS14285/DS14287 executes an update cycle once per second regardless of the SET bit in Register B.
When the SET bit in Register B is set to one, the user copy of the double buffered time, calendar, and
alarm bytes is frozen and will not update as the time increments. However, the time countdown chain
continues to update the internal copy of the buffer. This feature allows time to maintain accuracy
independent of reading or writing the time, calendar, and alarm buffers and also guarantees that time and
calendar information is consistent. The update cycle also compares each alarm byte with the
corresponding time byte and issues an alarm if a match or if a “don’t care” code is present in all three
positions.
There are three methods that can handle access of the real-time clock that avoid any possibility of
accessing inconsistent time and calendar data. The first method uses the update-ended interrupt. If
enabled, an interrupt occurs after every up date cycle that indicates that over 999 ms are available to read
valid time and date information. If this interrupt is used, the IRQF bit in Register C should be cleared
before leaving the interrupt routine.
A second method uses the update-in-progress bit (UIP) in Register A to determine if the update cycle is in
progress. The UIP bit will pulse once per second. After the UIP bit goes high, the update transfer occurs
244
s later. If a low is read on the UIP bit, the user has at least 244 s before the time/calendar data will
be changed. Therefore, the user should avoid interrupt service routines that would cause the time needed
to read valid time/calendar data to exceed 244
s.
The third method uses a periodic interrupt to determine if an update cycle is in progress. The UIP bit in
Register A is set high between the setting of the PF bit in Register C (see Figure 4). Periodic interrupts
that occur at a rate of greater than tBUC allow valid time and date information to be reached at each
occurrence of the periodic interrupt. The reads should be complete within 1 (tPI/
2 + tBUC) to ensure that
data is not read during the update cycle.
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| DS14285SN | 1 TIMER(S), REAL TIME CLOCK, PDSO24 |
| DS14285Q | 1 TIMER(S), REAL TIME CLOCK, PQCC28 |
| DS14285 | 1 TIMER(S), REAL TIME CLOCK, PDIP24 |
| DS1670S | 0 TIMER(S), REAL TIME CLOCK, PDSO20 |
| DS14287 | 1 TIMER(S), REAL TIME CLOCK, PDIP24 |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| DS14285N+ | 功能描述:實(shí)時時鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS14285Q | 功能描述:實(shí)時時鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS14285Q+ | 功能描述:實(shí)時時鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS14285QN | 功能描述:實(shí)時時鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
| DS14285QN+ | 功能描述:實(shí)時時鐘 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 總線接口:I2C 日期格式:DW:DM:M:Y 時間格式:HH:MM:SS RTC 存儲容量:64 B 電源電壓-最大:5.5 V 電源電壓-最小:1.8 V 最大工作溫度:+ 85 C 最小工作溫度: 安裝風(fēng)格:Through Hole 封裝 / 箱體:PDIP-8 封裝:Tube |
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