- 您現(xiàn)在的位置：買賣IC網(wǎng) > PDF目錄364683 > AN925 (意法半導(dǎo)體) Time Update in ST’s TIMEKEEPER Devices PDF資料下載
參數(shù)資料
| 型號(hào)： | AN925 |
| 廠商： | 意法半導(dǎo)體 |
| 英文描述： | Time Update in ST’s TIMEKEEPER Devices |
| 中文描述： | 時(shí)間更新ST的計(jì)時(shí)設(shè)備 |
| 文件頁(yè)數(shù)： | 1/5頁(yè) |
| 文件大?。?/td> | 32K |
| 代理商： | AN925 |
December 1998
1/4
AN925
APPLICATION NOTE
Time Update in ST’s TIMEKEEPER Devices
Figure 1 shows how the non-volatile, static memory array and the quartz controlled clock oscillator, of
TIMEKEEPER devices from STMicroelectronics, are interconnected through the clock registers. The clock
registers are mapped into the memory array (please see the data sheet for the precise mapping) as 8 or
16 BYTEWIDE BIPORT memory cells. The time data in these memory cells are updated from the clock
side (the system side) and are made available to the user side within the user’s finest time resolution.
However, the user’s finest time resolution is one second, so this leaves plenty of scope for variability (of
the order of several milliseconds) between one update and the next. Since this variability might be notice-
able to some applications (for example, those that poll the time registers regularly, or those that use an
alarm function that is triggered once per second), this document sets out to explain the nature of the var-
iability, to make it more predictable to the applications designer.
Figure 1. Internal Architecture of an ST TIMEKEEPER Device
AI02482
LITHIUM
CELL
OSCILLATOR AND
CLOCK CHAIN
VPFD
VCC
VSS
32,768 Hz
CRYSTAL
VOLTAGE SENSE
AND
SWITCHING
CIRCUITRY
8, 16 x 8
TIMEKEEPER
REGISTERS
SRAM ARRAY
A0-AX
DQ0-DQ7
POWER
WDI
E
W
G
BATTERY LOW
IRQ/FT
RST
INTEGRATED BATTERY
CRYSTAL AND
SNAPHAT
相關(guān)PDF資料 |
PDF描述 |
|---|---|
| AN9FSERIES | Analog master slice IC series |
| AN9DA00 | Analog master slice IC series |
| AN9DC00 | Analog master slice IC series |
| AN9DD00 | Analog master slice IC series |
| AN9DE00 | Analog master slice IC series |
相關(guān)代理商/技術(shù)參數(shù) |
參數(shù)描述 |
|---|---|
| AN929 | 制造商:MICROCHIP 制造商全稱:Microchip Technology 功能描述:Temperature Measurement Circuits for Embedded Applications |
| AN929/L12S | 制造商: 功能描述: 制造商:undefined 功能描述: |
| AN92910 | 制造商: 功能描述: 制造商:undefined 功能描述: |
| AN929-4 | 制造商:AN# - MILITARY 功能描述: 制造商: 功能描述: 制造商:undefined 功能描述: |
| AN929-4J | 制造商:AN# - MILITARY 功能描述: |
發(fā)布緊急采購(gòu)，3分鐘左右您將得到回復(fù)。