NXP Semiconductors LPC84x, Руководство пользователя

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UM11029 All information provided in this document is subject to legal disclaimers. © NXP Semiconductors N.V. 2017. All rights reserved.
User manual Rev. 1.0 — 16 June 2017 132 of 515
NXP Semiconductors
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Chapter 10: LPC84x Switch matrix (SWM)
10.4.2 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.
GPIO0 range from PIO0_0 to PIO0_31 and GPIO1 range from PIO1_0 to PIO1_21, for
assignment through the pin-assignment registers, are numbered 0 to 53.
There are two types of functions which must be assigned to port pins in different ways:
1.
Movable functions
(PINASSIGN0 to 14):
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 or PIO1_(n-32), 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 to 1):
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 or
PINENABLE1 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.
–
If a fixed-pin function is deselected and no movable function is assigned to this pin,
the pin is assigned its GPIO function.
–
On reset, all fixed-pin functions are deselected.
–
If a fixed-pin analog function is selected, its assigned pin cannot be used for any
other function.
T0_MAT3 O Timer Match channel 3 PINASSIGN14 Table 194
T0_CAP0 I Timer Capture channel 0 PINASSIGN14 Table 194
T0_CAP1 I Timer Capture channel 1 PINASSIGN14 Table 194
T0_CAP2 I Timer Capture channel 2 PINASSIGN14 Table 194
Table 178. Movable functions (assign to pins PIO0_0 to PIO0_31 and PIO1_0 to PIO1_21 through switch matrix)
Function name Type Description SWM Pin assign
register Reference