© Koninklijke Philips Electronics N.V. 2006. All rights reserved.
User manual
Rev. 01 — 12 January 2006
74
Philips Semiconductors
UM10161
Volume 1
Chapter 8: GPIO
Aside from the 32-bit long and word only accessible FIODIR register, every fast GPIO port
can also be controlled via several byte and half-word accessible registers listed in
. Next to providing the same functions as the FIODIR register, these additional
registers allow easier and faster access to the physical port pins.
8.4.2 Fast GPIO port 0 Mask register (FIOMASK, Port 0: FIO0MASK -
0x3FFF C010)
This register is available in the enhanced group of registers only. It is used to select the
port’s pins that will and will not be affected by a write accesses to the FIOPIN, FIOSET or
FIOCLR register. The mask register also filters out the port’s content when the FIOPIN
register is read.
A zero in this register’s bit enables an access to the corresponding physical pin via a read
or write access. If a bit in this register is one, the corresponding pin will not be changed
with write access and if read, will not be reflected in the updated FIOPIN register. For
software examples, see
Section 8.5 “GPIO usage notes” on page 78
Table 67:
Fast GPIO port 0 Direction register (FIO0DIR - address 0x3FFF C000) bit description
Bit
Symbol
Value Description
Reset value
31:0
FP0xDIR
0
Fast GPIO Direction control bits. Bit 0 in FIO0DIR controls P0.0 ... Bit 30 in
FIO0DIR controls P0.30.
Controlled pin is input.
0x0000 0000
1
Controlled pin is output.
Table 68:
Fast GPIO port 0 Direction control byte and half-word accessible register description
Register
name
Register
length (bits)
& access
Address
Description
Reset
value
FIO0DIR0
8 (byte)
0x3FFF C000
Fast GPIO Port 0 Direction control register 0. Bit 0 in FIO0DIR0
register corresponds to P0.0 ... bit 7 to P0.7.
0x00
FIO0DIR1
8 (byte)
0x3FFF C001
Fast GPIO Port 0 Direction control register 1. Bit 0 in FIO0DIR1
register corresponds to P0.8 ... bit 7 to P0.15.
0x00
FIO0DIR2
8 (byte)
0x3FFF C002
Fast GPIO Port 0 Direction control register 2. Bit 0 in FIO0DIR2
register corresponds to P0.16 ... bit 7 to P0.23.
0x00
FIO0DIR3
8 (byte)
0x3FFF C003
Fast GPIO Port 0 Direction control register 3. Bit 0 in FIO0DIR3
register corresponds to P0.24 ... bit 7 to P0.31.
0x00
FIO0DIRL
16
(half-word)
0x3FFF C000
Fast GPIO Port 0 Direction control Lower half-word register. Bit 0 in
FIO0DIRL register corresponds to P0.0 ... bit 15 to P0.15.
0x0000
FIO0DIRU
16
(half-word)
0x3FFF C002
Fast GPIO Port 0 Direction control Upper half-word register. Bit 0 in
FIO0DIRU register corresponds to P0.16 ... bit 15 to P0.31.
0x0000
Table 69:
Fast GPIO port 0 Mask register (FIO0MASK - address 0x3FFF C010) bit description
Bit
Symbol
Value Description
Reset value
31:0
FP0xMASK
0
Fast GPIO physical pin access control.
Pin is affected by writes to the FIOSET, FIOCLR, and FIOPIN registers.
Current state of the pin will be observable in the FIOPIN register.
0x0000 0000
1
Physical pin is unaffected by writes into the FIOSET, FIOCLR and FIOPIN
registers. When the FIOPIN register is read, this bit will not be updated with
the state of the physical pin.