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参数资料
| 型号： | M48T59V-70PC1TR |
| 厂商： | 意法半导体 |
| 英文描述： | 64 Kbit 8Kb x8 TIMEKEEPER SRAM |
| 中文描述： | 64千位8KB的x8 SRAM的计时器 |
| 文件页数： | 12/21页 |
| 文件大小： | 168K |
| 代理商： | M48T59V-70PC1TR |
M48T59, M48T59Y, M48T59V
12/21
cycle. The first 62 minutes in the cycle may, once
per minute, have one second either shortened by
128 or lengthened by 256 oscillator cycles. If a bi-
nary ’1’ is loaded into the register, only the first 2
minutes in the 64 minute cycle will be modified; if
a binary 6 is loaded, the first 12 will be affected,
and so on.
Therefore, each calibration step has the effect of
adding 512 or subtracting 256 oscillator cycles; for
every 125,829,120 actual oscillator cycles, that is
+4.068 or –2.034 ppm of adjustment per calibra-
tion step in the calibration register. Assuming that
the oscillator is in fact running at exactly 32,768Hz,
each of the 31 increments in the Calibration byte
would represent +10.7 or –5.35 seconds per
month which corresponds to a total range of +5.5
or –2.75 minutes per month.
Two methods are available for ascertaining how
much calibration a given M48T59/59Y/59V may
require. The first involves simply setting the clock,
letting it run for a month and comparing it to a
known accurate reference (like WWV broadcasts).
While that may seem crude, it allows the designer
to give the end user the ability to calibrate his clock
as his environment may require, even after the fi-
nal product is packaged in a non-user serviceable
enclosure. All the designer has to do is provide a
simple utility that accesses the Calibration byte.
The second approach is better suited to a manu-
facturing environment, and involves the use of the
IRQ/FT pin. The pin will toggle at 512Hz when the
Stop bit (D7 of 1FF9h) is '0', the FT bit (D6 of
1FFCh) is '1', the AFE bit (D7 of 1FF6h) is '0', and
the Watchdog Steering bit (D7 of 1FF7h) is '1' or
the Watchdog Register is reset (1FF7h = 0).
Any deviation from 512Hz indicates the degree
and direction of oscillator frequency shift at the test
temperature. For example, a reading of 512.01024
Hz would indicate a +20 ppm oscillator frequency
error, requiring a –10 (WR001010) to be loaded
into the Calibration Byte for correction. Note that
setting or changing the Calibration Byte does not
affect the Frequency test output frequency.
The IRQ/FT pin is an open drain output which re-
quires a pull-up resistor for proper operation. A
500-10k
resistor is recommended in order to
control the rise time. The FT bit is cleared on pow-
er-down.
For more information on calibration, see the Appli-
cation Note AN934 "TIMEKEEPER Calibration".
SETTING ALARM CLOCK
Registers 1FF5h-1FF2h contain the alarm set-
tings. The alarm can be configured to go off at a
prescribed time on a specific day of the month or
repeat every month, day, hour, minute, or second.
It can also be programmed to go off while the
M48T59 is in the battery back-up mode of opera-
tion to serve as a system wake-up call.
RPT1-RPT4 put the alarm in the repeat mode of
operation. Table 12 shows the possible configura-
tions. Codes not listed in the table default to the
once per second mode to quickly alert the user of
an incorrect alarm setting.
Figure 11. Interrupt Reset Waveforms
AI01388B
15ns Min
A0-A12
ACTIVE FLAG BIT
IRQ/FT
ADDRESS 1FF0h
HIGH-Z
Table 12. Alarm Repeat Mode
RPT4
RPT3
RPT2
RPT1
Alarm Activated
1
1
1
1
Once per Second
1
1
1
0
Once per Minute
1
1
0
0
Once per Hour
1
0
0
0
Once per Day
0
0
0
0
Once per Month
相关PDF资料 |
PDF描述 |
|---|---|
| M48T59V-70PC6 | 64 Kbit 8Kb x8 TIMEKEEPER SRAM |
| M48T59V-70PC6TR | 64 Kbit 8Kb x8 TIMEKEEPER SRAM |
| M48T59MH | 64 Kbit 8Kb x8 TIMEKEEPER SRAM |
| M48T59SH | 64 Kbit 8Kb x8 TIMEKEEPER SRAM |
| M48T59YPC | 5 PIN DIN CABLE 10 FT |
相关代理商/技术参数 |
参数描述 |
|---|---|
| M48T59V-70PC6 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:64 Kbit 8Kb x8 TIMEKEEPER SRAM |
| M48T59V-70PC6TR | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:64 Kbit 8Kb x8 TIMEKEEPER SRAM |
| M48T59VMH | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:64 Kbit 8Kb x8 TIMEKEEPER SRAM |
| M48T59VPC | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:64 Kbit 8Kb x8 TIMEKEEPER SRAM |
| M48T59VSH | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:64 Kbit 8Kb x8 TIMEKEEPER SRAM |
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