NXP Semiconductors LPC1768 - Page 129

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User manual Rev. 3 — 19 December 2013 129 of 841
NXP Semiconductors
UM10360
Chapter 9: LPC176x/5x General Purpose Input/Output (GPIO)
Only pins masked with zeros in the Mask register (see Section 9.5.5) will be correlated to
the current content of the Fast GPIO port pin value register.
Aside from the 32-bit long and word only accessible FIOxPIN register, every fast GPIO
port can also be controlled via several byte and half-word accessible register listed in
Table 110
, too. Next to providing the same functions as the FIOxPIN register, these
additional registers allow easier and faster access to the physical port pins.
Table 109. Fast GPIO port Pin value register (FIO0PIN to FIO4PIN- addresses 0x2009 C014 to
0x2009 C094) bit description
Bit Symbol Value Description Reset
value
31:0 FIO0VAL
FIO1VAL
FIO2VAL
FIO3VAL
FIO4VAL
Fast GPIO output value bits. Bit 0 corresponds to pin Px.0, bit 31
corresponds to pin Px.31. Only bits also set to 0 in the
FIOxMASK register are affected by a write or show the pin’s
actual logic state.
0x0
0 Reading a 0 indicates that the port pin’s current state is LOW.
Writing a 0 sets the output register value to LOW.
1 Reading a 1 indicates that the port pin’s current state is HIGH.
Writing a 1 sets the output register value to HIGH.
Table 110. Fast GPIO port Pin value byte and half-word accessible register
description
Generic
Register
name
Description Register
length (bits)
& access
Reset
value
PORTn Register
Address & Name
FIOxPIN0 Fast GPIO Port x Pin value
register 0. Bit 0 in FIOxPIN0
register corresponds to pin
Px.0 … bit 7 to pin Px.7.
8 (byte)
R/W
0x00 FIO0PIN0 - 0x2009 C014
FIO1PIN0 - 0x2009 C034
FIO2PIN0 - 0x2009 C054
FIO3PIN0 - 0x2009 C074
FIO4PIN0 - 0x2009 C094
FIOxPIN1 Fast GPIO Port x Pin value
register 1. Bit 0 in FIOxPIN1
register corresponds to pin
Px.8 … bit 7 to pin Px.15.
8 (byte)
R/W
0x00 FIO0PIN1 - 0x2009 C015
FIO1PIN1 - 0x2009 C035
FIO2PIN1 - 0x2009 C055
FIO3PIN1 - 0x2009 C075
FIO4PIN1 - 0x2009 C095
FIOxPIN2 Fast GPIO Port x Pin value
register 2. Bit 0 in FIOxPIN2
register corresponds to pin
Px.16 … bit 7 to pin Px.23.
8 (byte)
R/W
0x00 FIO0PIN2 - 0x2009 C016
FIO1PIN2 - 0x2009 C036
FIO2PIN2 - 0x2009 C056
FIO3PIN2 - 0x2009 C076
FIO4PIN2 - 0x2009 C096