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参数资料
| 型号： | DS12887 |
| 厂商： | DALLAS SEMICONDUCTOR |
| 元件分类： | Timer or RTC |
| 英文描述： | 1 TIMER(S), REAL TIME CLOCK, PDIP24 |
| 封装： | DIP-24 |
| 文件页数： | 16/19页 |
| 文件大小： | 584K |
| 代理商： | DS12887 |
DS12887
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TIME, CALENDAR AND ALARM LOCATIONS
The time and calendar information is obtained by reading the appropriate memory bytes. The time,
calendar, and alarm are set or initialized by writing the appropriate RAM bytes. The contents of the 10
time, calendar, and alarm bytes can be either Binary or Binary–Coded Decimal (BCD) format. Before
writing the internal time, calendar, and alarm registers, the SET bit in Register B should be written to a
logic 1 to prevent updates from occurring while access is being attempted. In addition to writing the 10
time, calendar, and alarm registers in a selected format (binary or BCD), the data mode bit (DM) of
Register B must be set to the appropriate logic level. All 10 time, calendar, and alarm bytes must use the
same data mode. The set bit in Register B should be cleared after the data mode bit has been written to
allow the real time clock to update the time and calendar bytes. Once initialized, the real time clock
makes all updates in the selected mode. The data mode cannot be changed without reinitializing the 10
data bytes. Table 2 shows the binary and BCD formats of the 10 time, calendar, and alarm locations. The
24–12 bit cannot be changed without reinitializing the hour locations.
When the 12–hour format is
selected, the high order bit of the hours byte represents PM when it is a logic 1. The time, calendar, and
alarm bytes are always accessible because they are double buffered. Once per second the 10 bytes are
advanced by 1 second and checked for an alarm condition. If a read of the time and calendar data occurs
during an update, a problem exists where seconds, minutes, hours, etc. may not correlate. The probability
of reading incorrect time and calendar data is low. Several methods of avoiding any possible incorrect
time and calendar reads are covered later in this text.
The three alarm bytes can be used in two ways. First, when the alarm time is written in the appropriate
hours, minutes, and seconds alarm locations, the alarm interrupt is initiated at the specified time each day
if the alarm enable bit is high. The second use condition is to insert a “don’t care” state in one or more of
the three alarm bytes. The “don’t care” code is any hexadecimal value from C0 to FF. The two most
significant bits of each byte set the “don’t care” condition when at logic 1. An alarm will be generated
each hour when the “don’t care” bits are set in the hours byte. Similarly, an alarm is generated every
minute with “don’t care” codes in the hours and minute alarm bytes. The “don’t care” codes in all three
alarm bytes create an interrupt every second.
TIME, CALENDAR AND ALARM DATA MODES Table 2
RANGE
ADDRESS
LOCATION
FUNCTION
DECIMAL
RANGE
BINARY DATA MODE
BCD DATA MODE
0
Seconds
0-59
00-3B
00-59
1
Seconds Alarm
0-59
00-3B
00-59
2
Minutes
0-59
00-3B
00-59
3
Minutes Alarm
0-59
00-3B
00-59
Hours-12-hr Mode
1-12
01-0C AM, 81-8C PM
01-12AM, 81-92PM
4
Hours-24-hr Mode
0-23
00-17
00-23
Hours Alarm-12-hr
1-12
01-0C AM, 81-8C PM
01-12AM, 81-92PM
5
Hours Alarm-24-hr
0-23
00-17
00-23
6
Day of the Week
Sunday = 1
1-7
01-07
7
Date of the Month
1-31
01-1F
01-31
8
Month
1-12
01-0C
01-12
9
Year
0-99
00-63
00-99
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相关代理商/技术参数 |
参数描述 |
|---|---|
| DS12887+ | 功能描述:实时时钟 RTC 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 |
| DS12887A | 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 |
| DS12887A+ | 功能描述:实时时钟 RTC 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 |
| DS1290 | 功能描述:计数器移位寄存器 RoHS:否 制造商:Texas Instruments 计数器类型: 计数顺序:Serial to Serial/Parallel 电路数量:1 封装 / 箱体:SOIC-20 Wide 逻辑系列: 逻辑类型: 输入线路数量:1 输出类型:Open Drain 传播延迟时间:650 ns 最大工作温度:+ 125 C 最小工作温度:- 40 C 封装:Reel |
| DS12C887 | 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 |
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