UM10850
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User manual
Rev. 2.4 — 13 September 2016
109 of 464
NXP Semiconductors
UM10850
Chapter 9: LPC5410x General Purpose I/O (GPIO)
9.5.1 GPIO port byte pin registers
Each GPIO pin has a byte register in this address range. Software typically reads and
writes bytes to access individual pins, but can read or write halfwords to sense or set the
state of two pins, and read or write words to sense or set the state of four pins.
9.5.2 GPIO port word pin registers
Each GPIO pin has a word register in this address range. Any byte, halfword, or word read
in this range will be all zeros if the pin is low or all ones if the pin is high, regardless of
direction, masking, or alternate function, except that pins configured as analog I/O always
read as zeros. Any write will clear the pin’s output bit if the value written is all zeros, else it
will set the pin’s output bit.
9.5.3 GPIO port direction registers
Each GPIO port has one direction register for configuring the port pins as inputs or
outputs.
Table 135. Address map B[0:49] registers
Peripheral
Base address
Offset
Increment
Dimension
GPIO
0x1C00 0000
[0x000:0x031]
0x1
50
Table 136. GPIO port byte pin registers (B[0:49], address offset [0x0000:0x0031]) bit description
Bit
Symbol
Description
Reset value
Access
0
PBYTE
Read: state of the pin PIOm_n, regardless of direction, masking, or alternate
function, except that pins configured as analog I/O always read as 0. One register
for each port pin. Supported pins depends on the specific device and package.
Write: loads the pin’s output bit.
Remark:
One register for each port pin. Supported pins depends on the specific
device and package.
ext
R/W
7:1
Reserved (0 on read, ignored on write)
0
-
Table 137. Address map W[0:49] registers
Peripheral
Base address
Offset
Increment
Dimension
GPIO
0x1C00 0000
[0x1000:0x10C4]
0x4
50
Table 138. GPIO port word pin registers (W[0:49], address offsets [0x1000:0x10C4]) bit description
Bit
Symbol
Description
Reset value
Access
31:0
PWORD
Read 0: pin PIOm_n is LOW.
Write 0: clear output bit.
Read 0xFFFF FFFF: pin PIOm_n is HIGH.
Write any value 0x0000 0001 to 0xFFFF FFFF: set output bit.
Remark:
Only 0 or 0xFFFF FFFF can be read. Writing any value other than 0 will
set the output bit. One register for each port pin. Supported pins depends on the
specific device and package.
ext
R/W