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参数资料
| 型号： | M48T513Y-70PM1 |
| 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, PDIP36 |
| 封装： | 0.600 INCH, PLASTIC, MODULE, DIP-36 |
| 文件页数： | 18/18页 |
| 文件大小： | 134K |
| 代理商： | M48T513Y-70PM1 |
9/18
M48T513Y, M48T513V
Table 10. Write Mode AC Characteristics
(TA = 0 to 70 °C)
Note: 1. CL = 5pF.
2. If E goes low simultaneously with W going low, the outputs remain in the high impedance state.
Symbol
Parameter
M48T513Y
M48T513V
Unit
-70
-85
Min
Max
Min
Max
tAVAV
Write Cycle Time
70
85
ns
tAVWL
Address Valid to Write Enable Low
0
ns
tAVEL
Address Valid to Chip Enable Low
0
ns
tWLWH
Write Enable Pulse Width
50
60
ns
tELEH
Chip Enable Low to Chip Enable High
55
65
ns
tWHAX
Write Enable High to Address Transition
5
ns
tEHAX
Chip Enable High to Address Transition
10
15
ns
tDVWH
Input Valid to Write Enable High
30
35
ns
tDVEH
Input Valid to Chip Enable High
30
35
ns
tWHDX
Write Enable High to Input Transition
5
ns
tEHDX
Chip Enable High to Input Transition
10
15
ns
tWLQZ
(1, 2)
Write Enable Low to Output Hi-Z
25
30
ns
tAVWH
Address Valid to Write Enable High
60
70
ns
tAVEH
Address Valid to Chip Enable High
60
70
ns
tWHQX
(1, 2)
Write Enable High to Output Transition
5
ns
WATCHDOG TIMER
The watchdog timer can be used to detect an out-
of-control microprocessor. The user programs the
watchdog timer by setting the desired amount of
time-out into the Watchdog Register, address
7FFF7h. Bits BMB4-BMB0 store a binary multiplier
and the two lower order bits RB1-RB0 select the
resolution, where 00 = 1/16 second, 01 = 1/4 sec-
ond, 10 = 1 second, and 11 = 4 seconds. The
amount of time-out is then determined to be the
multiplication of the five bit multiplier value with the
resolution. (For example: writing 00001110 in the
Watchdog Register = 3*1 or 3 seconds).
Note: Accuracy of timer is within ± the selected
resolution.
If the processor does not reset the timer within the
specified period, the M48T513Y/V sets the WDF
(Watchdog Flag) and generates a watchdog inter-
rupt or a microprocessor reset. WDF is reset by
reading the Flags Register (Address 7FFF0h). The
most significant bit of the Watchdog Register is the
Watchdog Steering Bit (WDS). When set to a '0',
the watchdog will activate the IRQ/FT pin when
timed-out. When WDS is set to a '1', the watchdog
will output a negative pulse on the RST pin for 40
to 200 ms. The Watchdog register and the FT bit
will reset to a '0' at the end of a Watchdog time-out
when the WDS bit is set to a '1'. The watchdog tim-
er can be reset by two methods: 1) a transition
(high-to-low or low-to-high) can be applied to the
Watchdog Input pin (WDI) or 2) the microproces-
sor can perform a write of the Watchdog Register.
The time-out period then starts over. The WDI pin
should be tied to VSS if not used. The watchdog
will be reset on each transition (edge) seen by the
WDI pin. In the order to perform a software reset
of the watchdog timer, the original time-out period
can be written into the Watchdog Register, effec-
tively restarting the count-down cycle.
Should the watchdog timer time-out, and the WDS
bit is programmed to output an interrupt, a value of
00h needs to be written to the Watchdog Register
in order to clear the IRQ/FT pin. This will also dis-
able the watchdog function until it is again pro-
grammed correctly. A read of the Flags Register
will reset the Watchdog Flag (Bit D7; Register
7FFF0h).
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相关代理商/技术参数 |
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| M48T513Y-85CS1 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
| M48T513Y-85PM1 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
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| M48T513YSH | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:3.3V-5V 4 Mbit 512Kb x8 TIMEKEEPER SRAM |
| M48T559 | 制造商:STMICROELECTRONICS 制造商全称:STMicroelectronics 功能描述:64 Kbit 8Kb x8 TIMEKEEPER SRAM with ADDRESS/DATA MULTIPLEXED |
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