TMS570LS1115 Datasheet, PDF (62/175 Pages) Texas Instruments – 16- and 32-Bit RISC Flash Microcontroller

TMS570LS1115
SPNS189B – OCTOBER 2012 – REVISED FEBRUARY 2015
www.ti.com
6.6.1.2 Low Power Oscillator
The Low Power Oscillator (LPO) is comprised of two oscillators — HF LPO and LF LPO, in a single
macro.
6.6.1.2.1 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.
• Supplies a high-frequency clock for non-timing-critical systems. This is connected as clock source # 5
of the Global Clock Module.
• Provides a comparison clock for the crystal oscillator failure detection circuit.
BIAS_EN
LFEN
LF_TRIM
HFEN
HF_TRIM
Low
Power
Oscillator
LFLPO
HFLPO
HFLPO_VALID
nPORRST
Figure 6-5. LPO Block Diagram
Figure 6-5 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.
Clock Detection
LPO - HF oscillator
(f_HFLPO)
LPO - LF oscillator
Table 6-10. LPO Specifications
Parameter
oscillator fail frequency - lower threshold, using
untrimmed LPO output
oscillator fail frequency - higher threshold, using
untrimmed LPO output
untrimmed frequency
trimmed frequency
startup time from STANDBY (LPO BIAS_EN High for
at least 900µs)
cold startup time
untrimmed frequency
startup time from STANDBY (LPO BIAS_EN High for
at least 900µs)
cold startup time
MIN
1.375
22
5.5
8
36
Typical
2.4
38.4
9
9.6
85
MAX
4.875
78
19.5
11
10
900
180
100
2000
Unit
MHz
MHz
MHz
MHz
µs
µs
kHz
µs
µs
62
System Information and Electrical Specifications
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