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参数资料
| 型号： | SH3001IMLTRT |
| 元件分类： | 时钟/数据恢复及定时提取 |
| 英文描述： | REAL TIME CLOCK, QCC16 |
| 封装： | 3 X 3 MM, 0.90 MM HEIGHT, LEAD FREE, MLP-16 |
| 文件页数： | 18/20页 |
| 文件大小： | 788K |
| 代理商： | SH3001IMLTRT |
SH3001 MicroBuddy
SYSTEM MANAGEMENT
Copyright 2002-2005 Semtech Corporation
7
V1.15
www.semtech.com
Special Operating Modes
The SH3001 can operate stand-alone, without
connections to the In and Out terminals of the host’s
oscillator. For example, a bank of SH3001 chips can
generate several different frequencies for simultaneous
use in the system, all controlled by a single micro (and
possibly sharing one 32.768 kHz crystal by chaining the
CLK32 pin to XIN pin on the next device). In this case
the CLKIN pin should be connected to VSS. The clock
output on the CLKOUT pin is continuous; the correct
operating mode is automatically recognized by the
SH3001.
Real-Time Support
The SH3001 has two support modules that are
specifically designed for various real time support
functions. They are the Real-Time Clock and the
Periodic Interrupt / Wakeup Timer. Both of these units
as well as other functions of the SH3001 depend on the
internal 32.768 kHz clock for accuracy.
With one external component (a 32.768 kHz crystal),
the SH3001 can provide a processor clock accuracy of
± 256 ppm (± 0.0256%) and the accuracy of the real-
time system of ± 4 ppm (± 0.0004%).
A microcontroller might not have a STOP command.
With the SH3001, this controller can do a “simulated”
STOP by issuing an instruction to the SH3001 to stop
the clock. This command is accepted only if the Periodic
Interrupt / Wakeup Timer has started (otherwise, once
the system is put to sleep, it would never wake up
again). This mode of operations is only possible if the
host processor is capable of correct operations with
clock frequency down to zero, and keeps all of the
internal RAM alive while the clock is stopped.
Low Frequency (LF) Oscillator System
This module provides the 32.768 kHz clock to all
internal circuits and to the dedicated output pin, CLK32.
If enabled, the CLK32 output continues normal
operations when VDD is absent and backup power is
available.
When the power is first applied to the SH3001, the
RC oscillator takes over. It supplies the 32.768 kHz
clock for start-up and initialization. Once the crystal has
started and stabilized, the internal 32.768 kHz clock
switches to the very accurate crystal frequency; see
Figure 2.
5
6
7
VREG
RC
Oscillator
13
Internal
32.768 kHz
Clock
X-tal stable?
Internal RREF
32.768 kHz
Crystal
12.5 pF Load
Capacitance
Figure 2. Simplified LF Oscillator System
1
CLK32
XIN
XOUT
CLKSEL
8
VSS
CLK32 ON
4-bit Value
6-bit Value
4-bit Value
Lock / Unlock
Logic
Lock Logic
INTERNAL
RREF ON
From / To
Serial I/O
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相关代理商/技术参数 |
参数描述 |
|---|---|
| SH3002 | 制造商:SEMTECH 制造商全称:Semtech Corporation 功能描述:Reset Management and Clock Management Support IC for Microcontrollers |
| SH3002-DC70A | 制造商:ROHM 制造商全称:Rohm 功能描述:Near edge thermal printhead (with thermal historical control) |
| SH3002-DC80A | 制造商:ROHM 制造商全称:Rohm 功能描述:Near edge thermal printhead (with thermal historical control) |
| SH3002-DC90A | 制造商:ROHM 制造商全称:Rohm 功能描述:Near edge type thermal printhead(11.81dots / mm) |
| SH3002-DC90A_09 | 制造商:ROHM 制造商全称:Rohm 功能描述:Near edge type thermal printhead(11.81dots / mm) |
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