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UM10601
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© NXP B.V. 2012. All rights reserved.
Preliminary user manual
Rev. 1.0 — 7 November 2012
78 of 313
NXP Semiconductors
UM10601
Chapter 7: LPC800 GPIO port
7.6.3 GPIO port direction registers
Each GPIO port has one direction register for configuring the port pins as inputs or
outputs.
7.6.4 GPIO port mask registers
These registers affect writing and reading the MPORT registers. Zeroes in these registers
enable reading and writing; ones disable writing and result in zeros in corresponding
positions when reading.
7.6.5 GPIO port pin registers
Reading these registers returns the current state of the pins read, regardless of direction,
masking, or alternate functions, except that pins configured as analog I/O always read as
0s. Writing these registers loads the output bits of the pins written to, regardless of the
Mask register.
Table 70.
GPIO port 0 word pin registers (W[0:17], addresses 0xA000 1000 (W0) to 0x5000
1048 (W17)) bit description
Bit
Symbol
Description
Reset
value
Access
31:0
PWORD Read 0: pin is LOW.
Write 0: clear output bit.
Read 0xFFFF FFFF: pin 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.
ext
R/W
Table 71.
GPIO direction port 0 register (DIR0, address 0xA000 2000) bit description
Bit
Symbol
Description
Reset
value
Access
17:0
DIRP0
Selects pin direction for pin PIO0_n (bit 0 = PIO0_0, bit 1 =
PIO0_1, ..., bit 17 = PIO0_17).
0 = input.
1 = output.
0
R/W
31:18 -
Reserved.
0
-
Table 72.
GPIO mask port 0 register (MASK0, address 0xA000 2080) bit description
Bit
Symbol
Description
Reset
value
Access
17:0
MASKP0 Controls which bits corresponding to PIO0_n are active in the
P0MPORT register (bit 0 = PIO0_0, bit 1 = PIO0_1, ..., bit 17
= PIO0_17).
0 = Read MPORT: pin state; write MPORT: load output bit.
1 = Read MPORT: 0; write MPORT: output bit not affected.
0
R/W
31:18 -
Reserved.
0
-