UM10360 All information provided in this document is subject to legal disclaimers. © NXP B.V. 2013. All rights reserved.
User manual Rev. 3 — 19 December 2013  126 of 841
NXP Semiconductors
UM10360
Chapter 9: LPC176x/5x General Purpose Input/Output (GPIO)
Access to a port pin via the FIOxSET register is conditioned by the corresponding bit of 
the FIOxMASK register (see Section 9.5.5
).
 
Aside from the 32-bit long and word only accessible FIOxSET register, every fast GPIO 
port can also be controlled via several byte and half-word accessible registers listed in 
Table 106
, too. Next to providing the same functions as the FIOxSET register, these 
additional registers allow easier and faster access to the physical port pins.
 
Table 105. Fast GPIO port output Set register (FIO0SET to FIO4SET - addresses 0x2009 C018 
to 0x2009 C098) bit description
Bit Symbol Value Description Reset 
value
31:0 FIO0SET
FIO1SET
FIO2SET
FIO3SET
FIO4SET
Fast GPIO output value Set bits. Bit 0 in FIOxSET controls pin 
Px.0, bit 31 in FIOxSET controls pin Px.31.
0x0
0 Controlled pin output is unchanged.
1 Controlled pin output is set to HIGH.
Table 106. Fast GPIO port output Set byte and half-word accessible register description
Generic 
Register 
name
Description Register 
length (bits)
& access
Reset 
value
PORTn Register 
Address & Name
FIOxSET0 Fast GPIO Port x output Set 
register 0. Bit 0 in FIOxSET0 
register corresponds to pin 
Px.0 … bit 7 to pin Px.7.
8 (byte)
R/W
0x00 FIO0SET0 - 0x2009 C018
FIO1SET0 - 0x2009 C038
FIO2SET0 - 0x2009 C058
FIO3SET0 - 0x2009 C078
FIO4SET0 - 0x2009 C098
FIOxSET1 Fast GPIO Port x output Set 
register 1. Bit 0 in FIOxSET1 
register corresponds to pin 
Px.8 … bit 7 to pin Px.15.
8 (byte)
R/W
0x00 FIO0SET1 - 0x2009 C019
FIO1SET1 - 0x2009 C039
FIO2SET1 - 0x2009 C059
FIO3SET1 - 0x2009 C079
FIO4SET1 - 0x2009 C099
FIOxSET2 Fast GPIO Port x output Set 
register 2. Bit 0 in FIOxSET2 
register corresponds to pin 
Px.16 … bit 7 to pin Px.23.
8 (byte)
R/W
0x00 FIO0SET2 - 0x2009 C01A
FIO1SET2 - 0x2009 C03A
FIO2SET2 - 0x2009 C05A
FIO3SET2 - 0x2009 C07A
FIO4SET2 - 0x2009 C09A
FIOxSET3 Fast GPIO Port x output Set 
register 3. Bit 0 in FIOxSET3 
register corresponds to pin 
Px.24 … bit 7 to pin Px.31.
8 (byte)
R/W
0x00 FIO0SET3 - 0x2009 C01B
FIO1SET3 - 0x2009 C03B
FIO2SET3 - 0x2009 C05B
FIO3SET3 - 0x2009 C07B
FIO4SET3 - 0x2009 C09B
FIOxSETL Fast GPIO Port x output Set 
Lower half-word register. Bit 0 
in FIOxSETL register 
corresponds to pin Px.0 … bit 
15 to pin Px.15.
16 (half-word)
R/W
0x0000 FIO0SETL - 0x2009 C018
FIO1SETL - 0x2009 C038
FIO2SETL - 0x2009 C058
FIO3SETL - 0x2009 C078
FIO4SETL - 0x2009 C098
FIOxSETU Fast GPIO Port x output Set 
Upper half-word register. Bit 0 
in FIOxSETU register 
corresponds to Px.16 … bit 
15 to Px.31.
16 (half-word)
R/W
0x0000 FIO0SETU - 0x2009 C01A
FIO1SETU - 0x2009 C03A
FIO2SETU - 0x2009 C05A
FIO3SETU - 0x2009 C07A
FIO4SETU - 0x2009 C09A