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TMS570LS2125 Datasheet, PDF (52/154 Pages) Texas Instruments – TMS570LSxxx5 16/32-Bit RISC Flash Microcontroller
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TMS570LS2125
TMS570LS2135
TMS570LS3135
SPNS164 – SEPTEMBER 2011
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4.3.2 Power-Down Sequence
The different supplies to the device can be powered down in any order.
4.3.3 Power-On Reset: nPORRST
This is the power-on reset. This reset must be asserted by an external circuitry whenever the I/O or core
supplies are outside the specified recommended range. This signal has a glitch filter on it. It also has an
internal pulldown.
4.3.3.1 nPORRST Electrical and Timing Requirements
NO Parameter
VCCPORL
VCCPORH
VCCIOPORL
VCCIOPORH
VIL(PORRST)
3 tsu(PORRST)
6 th(PORRST)
7 tsu(PORRST)
8 th(PORRST)
9 th(PORRST)
tf(nPORRST)
Table 4-4. Electrical Requirements for nPORRST
VCC low supply level when nPORRST must be active during
power-up
VCC high supply level when nPORRST must remain active during
power-up and become active during power down
VCCIO / VCCP low supply level when nPORRST must be active during
power-up
VCCIO / VCCP high supply level when nPORRST must remain active
during power-up and become active during power down
Low-level input voltage of nPORRST VCCIO > 2.5V
Low-level input voltage of nPORRST VCCIO < 2.5V
Setup time, nPORRST active before VCCIO and VCCP > VCCIOPORL
during power-up
Hold time, nPORRST active after VCC > VCCPORH
Setup time, nPORRST active before VCC < VCCPORH during power
down
Hold time, nPORRST active after VCCIO and VCCP > VCCIOPORH
Hold time, nPORRST active after VCC < VCCPORL
Filter time nPORRST pin;
pulses less than MIN will be filtered out, pulses greater than MAX
will generate a reset.
MIN
1.14
3.0
0
1
2
1
0
500
MAX
0.5
1.1
0.2 * VCCIO
0.5
2000
Unit
V
V
V
V
V
V
ms
ms
µs
ms
ms
ns
3.3 V
VCCIOPORH
8
VCCIO / VCCP
VCCIOPORH
1.2 V
VCCPORH
6
VCC (1.2 V)
VCCIO / VCCP(3.3 V)
nPORRST
VCCIOPORL
VCCPORL
3
VIL(PORRST)
7
VCC
6
VIL
VIL
VCCPORH
7
VCCPORL
VCCIOPORL
9
VIL
VIL(PORRST)
NOTE: There is no timing dependency between the ramp of the VCCIO and the VCC supply voltage; this is just an exemplary drawing.
Figure 4-1. nPORRST Timing Diagram
52
System Information and Electrical Specifications
Copyright © 2011, Texas Instruments Incorporated
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