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参数资料
| 型号： | M48T35AY-70MH6TR |
| 厂商： | STMICROELECTRONICS |
| 元件分类： | 时钟/数据恢复及定时提取 |
| 英文描述： | 0 TIMER(S), REAL TIME CLOCK, PDSO28 |
| 封装： | 0.330 INCH, PLASTIC, SOH-28 |
| 文件页数： | 3/25页 |
| 文件大小： | 510K |
| 代理商： | M48T35AY-70MH6TR |
11/25
M48T35AY, M48T35AV
CLOCK OPERATIONS
Reading the Clock
Updates to the TIMEKEEPER registers (see Ta-
ble 5) should be halted before clock data is read to
prevent reading data in transition. The BiPORT
TIMEKEEPER cells in the RAM array are only
data registers and not the actual clock counters,
so updating the registers can be halted without
disturbing the clock itself.
Updating is halted when a '1' is written to the
READ Bit, D6 in the Control Register 7FF8h. As
long as a '1' remains in that position, updating is
halted.
After a halt is issued, the registers reflect the
count; that is, the day, date, and the time that were
current at the moment the halt command was is-
sued.
All of the TIMEKEEPER registers are updated si-
multaneously. A halt will not interrupt an update in
progress. Updating is within a second after the bit
is reset to a '0.'
Setting the Clock
Bit D7 of the Control Register 7FF8h is the WRITE
Bit. Setting the WRITE Bit to a '1,' like the READ
Bit, halts updates to the TIMEKEEPER registers.
The user can then load them with the correct day,
date, and time data in 24 hour BCD format (see
Table 5). Resetting the WRITE Bit to a '0' then
transfers the values of all time registers 7FF9h-
7FFFh to the actual TIMEKEEPER counters and
allows normal operation to resume. The FT Bit and
the bits marked as '0' in Table 5 must be written to
'0' to allow for normal TIMEKEEPER and RAM op-
eration. After the WRITE Bit is reset, the next clock
update will occur within one second.
See the Application Note AN923, “TIMEKEEPER
Rolling Into the 21st Century” for information on
Century Rollover.
Stopping and Starting the Oscillator
The oscillator may be stopped at any time. If the
device is going to spend a significant amount of
time on the shelf, the oscillator can be turned off to
minimize current drain on the battery. The STOP
Bit is the MSB of the seconds register. Setting it to
a '1' stops the oscillator. The M48T35AY/V is
shipped from STMicroelectronics with the STOP
Bit set to a '1.' When reset to a '0,' the M48T35AY/
V oscillator starts within 1 second.
Table 5. Register Map
Keys: S = SIGN Bit
FT = FREQUENCY TEST Bit (Must be set to '0' upon power
for normal operation)
R = READ Bit
W = WRITE Bit
ST = STOP Bit
0 = Must be set to '0'
CEB = Century Enable Bit
CB = Century Bit
Note: When CEB is set to '1,' CB will toggle from '0' to '1' or from '1' to '0' at the turn of the century (dependent upon the initial value set).
When CEB is set to '0,' CB will not toggle. The WRITE Bit does not need to be set to write to CEB.
Address
Data
Function/Range
BCD Format
D7
D6
D5
D4
D3
D2
D1
D0
7FFFh
10 Years
Year
00-99
7FFEh
0
10 M.
Month
01-12
7FFDh
0
10 Date
Date
01-31
7FFCh
0
FT
CEB
CB
0
Day
Century/Day
00-01/01-07
7FFBh
0
10 Hours
Hours
00-23
7FFAh
0
10 Minutes
Minutes
00-59
7FF9h
ST
10 Seconds
Seconds
00-59
7FF8h
W
R
S
Calibration
Control
相关PDF资料 |
PDF描述 |
|---|---|
| M48T35AV-10MH1 | 0 TIMER(S), REAL TIME CLOCK, PDSO28 |
| M48T35AY-70MH1F | REAL TIME CLOCK, PDSO28 |
| M48T35AV-10MH6E | REAL TIME CLOCK, PDSO28 |
| M48T35Y-70PM1 | 0 TIMER(S), REAL TIME CLOCK, PDIP28 |
| M48T35Y-70MH6TR | 0 TIMER(S), REAL TIME CLOCK, PDSO28 |
相关代理商/技术参数 |
参数描述 |
|---|---|
| M48T35AY-70PC1 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:256 Kbit 32Kb x8 TIMEKEEPER SRAM |
| M48T35AY-70PC1E | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:5.0 or 3.3V, 256 Kbit (32 Kb x8) TIMEKEEPER㈢ SRAM |
| M48T35AY-70PC1F | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:5.0 or 3.3V, 256 Kbit (32 Kb x8) TIMEKEEPER㈢ SRAM |
| M48T35AY-70PC1TR | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:5.0 or 3.3V, 256 Kbit (32 Kb x8) TIMEKEEPER㈢ SRAM |
| M48T35AY-70PC6 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:256 Kbit 32Kb x8 TIMEKEEPER SRAM |
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