Texas Instruments Hercules TMS570LS04x/03x LaunchPad Evaluation Kit LAUNCHXL-TMS57004 LAUNCHXL-TMS57004 数据表
产品代码
LAUNCHXL-TMS57004
BIAS_EN
Low
Power
Oscillator
LFEN
LF_TRIM
HFEN
HF_TRIM
CLK80K
CLK10M
CLK10M_VALID
nPORRST
SPNS186A – OCTOBER 2012 – REVISED SEPTEMBER 2013
4.5.1.2
Low Power Oscillator
The Low Power Oscillator (LPO) is comprised of two oscillators — HF LPO and LF LPO, in a single
macro.
macro.
4.5.1.2.1 Features
The main features of the LPO are:
•
Supplies a clock at extremely low power for power-saving modes. This is connected as clock source #
4 of the Global Clock Module.
4 of the Global Clock Module.
•
Supplies a high-frequency clock for non-timing-critical systems. This is connected as clock source # 5
of the Global Clock Module.
of the Global Clock Module.
•
Provides a comparison clock for the crystal oscillator failure detection circuit.
Figure 4-5. LPO Block Diagram
shows a block diagram of the internal reference oscillator. This is a low power oscillator (LPO)
and provides two clock sources: one nominally 80KHz and one nominally 10MHz.
4.5.1.2.2 LPO Electrical and Timing Specifications
Table 4-10. LPO Specifications
Parameter
MIN
Typical
MAX
Unit
Clock Detection
oscillator fail frequency - lower threshold, using
1.375
2.4
4.875
MHz
untrimmed LPO output
oscillator fail frequency - higher threshold, using
22
38.4
78
MHz
untrimmed LPO output
LPO - HF oscillator
untrimmed frequency
5.5
9
19.5
MHz
(f
HFLPO
)
trimmed frequency
8
9.6
11
MHz
startup time from STANDBY (LPO BIAS_EN High for
10
µs
at least 900µs)
cold startup time
900
µs
LPO - LF oscillator
untrimmed frequency
36
85
180
kHz
startup time from STANDBY (LPO BIAS_EN High for
100
µs
at least 900µs)
cold startup time
2000
µs
Copyright © 2012–2013, Texas Instruments Incorporated
System Information and Electrical Specifications
33
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