Datasheet

LPC84x All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2018. All rights reserved.
Product data sheet Rev. 1.7 — 27 February 2018 76 of 97
NXP Semiconductors
LPC84x
32-bit Arm Cortex-M0+ microcontroller
14. Application information
14.1 Start-up behavior
Figure 36 shows the start-up timing after reset. The FRO 12 MHz oscillator provides the
default clock at Reset and provides a clean system clock shortly after the supply pins
reach operating voltage.
Fig 36. Start-up timing
Table 33. Typical start-up timing parameters
Parameter Description Value
t
a
FRO start time  26 s
t
b
Internal reset de-asserted 101 s
t
c
Boot time 51 s
aaa-027486
valid threshold
= 1.8 V
processor status
V
DD
FRO status
internal reset
GND
boot time
user code
boot code
execution
finishes;
user code starts
FRO
starts
supply ramp-up
time
t
b
µst
a
µs
t
c
µs