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参数资料
| 型号： | DS12CR887-33+ |
| 厂商： | Maxim Integrated Products |
| 文件页数： | 13/23页 |
| 文件大小： | 0K |
| 描述： | IC RTC W/RAM 128 BYTE 24-EDIP |
| 产品培训模块： | Lead (SnPb) Finish for COTS Obsolescence Mitigation Program |
| 标准包装： | 31 |
| 类型： | 时钟/日历 |
| 特点： | 警报器，闰年，NVSRAM，方波输出，涓流充电器 |
| 存储容量： | 114B |
| 时间格式： | HH:MM:SS（12/24 小时） |
| 数据格式： | YY-MM-DD-dd |
| 接口： | 并联 |
| 电源电压： | 2.97 V ~ 3.63 V |
| 工作温度： | -40°C ~ 85°C |
| 安装类型： | 通孔 |
| 封装/外壳： | 24-DIP 模块（0.600"，15.24mm） |
| 供应商设备封装： | 24-EDIP |
| 包装： | 管件 |
| 产品目录页面： | 1433 (CN2011-ZH PDF) |
DS12R885/DS12CR887/DS12R887
RTCs with Constant-Voltage Trickle Charger
20
Maxim Integrated
Update Cycle
The DS12R885 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 1, the user copy of the
double-buffered time, calendar, and alarm bytes is
frozen and does 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 read-
ing 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 RTC access
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 update cycle that indicates over 999ms is avail-
able 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 pulses once per second. After
the UIP bit goes high, the update transfer occurs 244s
later. If a low is read on the UIP bit, the user has at least
244s before the time/calendar data is changed.
Therefore, the user should avoid interrupt service rou-
tines that would cause the time needed to read valid
time/calendar data to exceed 244s.
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
(Figure 3). Periodic interrupts that occur at a rate 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 one (tPI/2 + tBUC)
to ensure that data is not read during the update cycle.
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
122.070s
8.192kHz
0
1
0
244.141s
4.096kHz
0
1
0
1
488.281s
2.048kHz
0
1
0
976.5625s
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
Table 3. Periodic Interrupt Rate and
Square-Wave Output Frequency
UIP
UF
PF
tBUC = DELAY TIME BEFORE UPDATE
CYCLE = 244
μs
1 SECOND
tPI
tPI/2
tBUC
Figure 3. UIP and Periodic Interrupt Timing
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS12CR887-33+ | 功能描述:实时时钟 RTC w/Constant V Trickle Charger RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| DS12CR887-5 | 功能描述:实时时钟 RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| DS12CR887-5+ | 功能描述:实时时钟 RTC w/Constant V Trickle Charger RoHS:否 制造商:Microchip Technology 功能:Clock, Calendar. Alarm RTC 总线接口:I2C 日期格式:DW:DM:M:Y 时间格式:HH:MM:SS RTC 存储容量:64 B 电源电压-最大:5.5 V 电源电压-最小:1.8 V 最大工作温度:+ 85 C 最小工作温度: 安装风格:Through Hole 封装 / 箱体:PDIP-8 封装:Tube |
| DS12R885-33 | 制造商:Maxim Integrated Products 功能描述:REAL TIME CLOCK MULTIPLEXED 114BYTE - Bulk |
| DS12R885-5 | 制造商:Maxim Integrated Products 功能描述:REAL TIME CLOCK MULTIPLEXED 114BYTE - Bulk |
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