Chapter 3: System Control Block; Summary Of System Control Block Functions; Pin Description - Philips LPC2101 User Manual

3.1 Summary of system control block functions

The System control block includes several system features and control registers for a
number of functions that are not related to specific peripheral devices. These include:
Each type of function has its own register(s) if any are required, and unneeded bits are
defined as reserved in order to allow future expansion. Unrelated functions never share
the same register addresses

3.2 Pin description

Table 5
Table 5:
User manual
UM10161

Chapter 3: System control block

Rev. 01 — 12 January 2006
•
Crystal oscillator
•
External interrupt inputs
•
Miscellaneous system controls and status
•
Memory mapping control
•
PLL
•
Power control
•
Reset
•
APB divider
•
Wake-up timer
shows pins that are associated with System Control block functions.
Pin summary
Pin name Pin
direction
X1 Input
X2 Output
EINT0 Input
EINT1 Input
EINT2 Input
RESET Input
Rev. 01 — 12 January 2006
Pin description
Crystal Oscillator Input - Input to the oscillator and internal clock
generator circuits
Crystal Oscillator Output - Output from the oscillator amplifier
External Interrupt Input 0 - An active LOW/HIGH level or
falling/rising edge general purpose interrupt input. This pin may be
used to wake up the processor from Idle or Power-down modes.
Pin P0.16 can be selected to perform EINT0 function.
External Interrupt Input 1 - See the EINT0 description above.
Pin P0.14 can be selected to perform EINT1 function.
Important: LOW level on pin P0.14 immediately after reset is
considered as an external hardware request to start the ISP
command handler. More details on ISP and Serial Boot Loader can
be found in Section 19.4 on page
External Interrupt Input 2 - See the EINT0 description above.
Pins P0.7 and P0.15 can be selected to perform EINT2 function.
External Reset input - A LOW on this pin resets the chip, causing
I/O ports and peripherals to take on their default states, and the
processor to begin execution at address 0x0000 0000.
User manual
229.
© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
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