
UM10800
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© NXP Semiconductors N.V. 2016. All rights reserved.
User manual
Rev. 1.2 — 5 October 2016
80 of 487
NXP Semiconductors
UM10800
Chapter 7: LPC82x Switch matrix (SWM)
7.4.2 Switch matrix register interface
The switch matrix consists of two blocks of pin-assignment registers PINASSIGN and
PINENABLE. Every function has an assigned field (1-bit or 8-bit wide) within this bank of
registers where you can program the external pin - identified by its GPIO function - you
want the function to connect to.
GPIOs range from PIO0_0 to PIO0_28 and, for assignment through the pin-assignment
registers, are numbered 0 to 28.
There are two types of functions which must be assigned to port pins in different ways:
1.
Movable functions
(PINASSIGN0 to 11):
All movable functions are digital functions. Assign movable functions to pin numbers
through the 8 bits of the PINASSIGN register associated with this function. Once the
function is assigned a pin PIO0_n, it is connected through this pin to a physical pin on
the package.
Remark:
You can assign only one digital output function to an external pin at any
given time.
Remark:
You can assign more than one digital input function to one external pin.
2.
Fixed-pin functions
(PINENABLE0):
Some functions require pins with special characteristics and cannot be moved to
other physical pins. Hence these functions are mapped to a fixed port pin. Examples
of fixed-pin functions are the oscillator pins or comparator inputs.
Each fixed-pin function is associated with one bit in the PINENABLE0 register which
selects or deselects the function.
–
If a fixed-pin function is deselected, any movable function can be assigned to its
port and pin.
SCT_OUT2
O
SCT output 2.
PINASSIGN8
SCT_OUT3
O
SCT output 3.
PINASSIGN8
SCT_OUT4
O
SCT output 4.
PINASSIGN8
SCT_OUT5
O
SCT output 5.
PINASSIGN9
I2C1_SDA
I/O
I
2
C1-bus data input/output.
PINASSIGN9
I2C1_SCL
I/O
I
2
C1-bus clock input/output.
PINASSIGN9
I2C2_SDA
I/O
I
2
C2-bus data input/output.
PINASSIGN9
I2C2_SCL
I/O
I
2
C2-bus clock input/output.
PINASSIGN10
I2C3_SDA
I/O
I
2
C3-bus data input/output.
PINASSIGN10
I2C3_SCL
I/O
I
2
C3-bus clock input/output.
PINASSIGN10
ADC_PINTRIG0
I
ADC external pin trigger input 0.
PINASSIGN10
ADC_PINTRIG1
I
ADC external pin trigger input 1.
PINASSIGN11
ACMP_O
O
Analog comparator output.
PINASSIGN11
CLKOUT
O
Clock output.
PINASSIGN11
GPIO_INT_BMAT
O
Output of the pattern match engine.
PINASSIGN11
Table 65.
Movable functions (assign to pins PIO0_0 to PIO0_28 through switch matrix)
Function name
Type
Description
SWM Pin assign
register
Reference