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DS12885Q 参数 Datasheet PDF下载

DS12885Q图片预览
型号: DS12885Q
PDF下载: 下载PDF文件 查看货源
内容描述: 实时时钟 [Real-Time Clock]
分类和应用: 计时器或实时时钟微控制器和处理器
文件页数/大小: 22 页 / 259 K
品牌: MAXIM [ MAXIM INTEGRATED PRODUCTS ]
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Real-Time Clock  
5/DS12C87A  
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 inter-  
rupt is initiated at the specified time each day, if the  
alarm-enable bit is high. In this mode, the “0” bits in the  
alarm registers and the corresponding time registers  
must always be written to 0 (Table 2A and 2B). Writing  
the 0 bits in the alarm and/or time registers to 1 can  
result in undefined operation.  
condition when at logic 1. An alarm is 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.  
All 128 bytes can be directly written or read, except for  
the following:  
1) Registers C and D are read-only.  
2) Bit 7 of register A is read-only.  
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  
3) The MSB of the seconds byte is read-only.  
Table 2A. Time, Calendar, and Alarm Data Modes—BCD Mode (DM = 0)  
ADDRESS  
BIT 7  
BIT 6 BIT 5  
BIT 4  
BIT 3  
BIT 2  
BIT 1  
BIT 0  
FUNCTION  
RANGE  
00H  
0
10 Seconds  
Seconds  
Seconds  
00–59  
01H  
02H  
03H  
0
10 Seconds  
10 Minutes  
10 Minutes  
Seconds  
Minutes  
Minutes  
Seconds Alarm  
Minutes  
00–59  
00–59  
00–59  
0
0
Minutes Alarm  
AM/PM  
0
0
0
10 Hours  
10 Hours  
10 Hours  
10 Hours  
1–12 +AM/PM  
00–23  
04H  
05H  
0
0
Hours  
Hours  
Hours  
0
AM/PM  
1–12 +AM/PM  
00–23  
Hours Alarm  
0
0
0
0
06H  
07H  
0
0
0
0
0
Day  
Day  
Date  
01–07  
01–31  
01–12  
00–99  
10 Date  
Date  
Month  
Year  
08H  
0
10 Months  
Month  
Year  
09H  
10 Years  
0AH  
UIP  
SET  
IRQF  
VRT  
X
DV2  
PIE  
PF  
0
DV1  
AIE  
AF  
0
DV0  
UIE  
UF  
0
RS3  
RS2  
RS1  
RS0  
DSE  
0
Control  
Control  
Control  
Control  
RAM  
0BH  
SQWE  
DM  
0
24/12  
0CH  
0
0
X
0
0
X
0DH  
0
0
0EH-31H  
32H  
X
X
X
X
X
10 Century  
Century  
Century*  
RAM  
00–99  
33H-7FH  
X
X
X
X
X
X
X
X
X = Read/Write Bit.  
*DS12C887, DS12C887A only. General-purpose RAM on DS12885, DS12887, and DS12887A.  
Note: Unless otherwise specified, the state of the registers is not defined when power is first applied. Except for the seconds regis-  
ter, 0 bits in the time and date registers can be written to 1, but may be modified when the clock updates. 0 bits should always be  
written to 0 except for alarm mask bits.  
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