Nxp Semiconductors UM10237 用户手册
UM10237_2
© NXP B.V. 2008. All rights reserved.
User manual
Rev. 02 — 19 December 2008
34 of 792
NXP Semiconductors
UM10237
Chapter 3: LPC24XX System control
The various Resets have some small differences. For example, a Power On Reset causes
the value of certain pins to be latched to configure the part.
the value of certain pins to be latched to configure the part.
For more details on Reset, PLL and startup/boot code interaction see
3.2.1 Reset Source Identification Register (RSIR - 0xE01F C180)
This register contains one bit for each source of Reset. Writing a 1 to any of these bits
clears the corresponding read-side bit to 0. The interactions among the four sources are
described below.
clears the corresponding read-side bit to 0. The interactions among the four sources are
described below.
Fig 11. Example of start-up after reset
valid threshold
processor status
V
DD(3V3)
IRC status
RESET
GND
002aad482
30
μ
s
1
μ
s; IRC stability count
8
μ
s
170
μ
s
160
μ
s
boot time
user code
boot code
execution
finishes;
user code starts
IRC
starts
IRC
stable
flash read
finishes
flash read
starts
supply ramp-up
time