UM10413
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© NXP B.V. 2011. All rights reserved.
User manual
Rev. 1 — 16 December 2011
70 of 268
NXP Semiconductors
UM10413
MPT612 User manual
Aside from the 32-bit long and word-only accessible register FIOMASK, every fast GPIO
pin can also be controlled via several byte and half-word accessible registers listed in
. Next to providing the same functions as register FIOMASK, these additional
registers allow easier and faster access to the physical pins.
13.4.3 GPIO Pin value register (IOPIN, IO0PIN - 0xE002 8000; FIOPIN, FIO0PIN -
0x3FFF C014)
This register provides the values of pins that are configured to perform only digital
functions. The register gives the logic value of the pin regardless of whether the pin is
configured for input or output, or as GPIO or an alternate digital function. As an example,
a particular pin can have GPIO input or GPIO output, UART receive, and PWM output as
selectable functions. Any configuration of that pin allows its current logic state to be read
from register IOPIN.
If a pin has an analog function as one of its options, the pin state cannot be read if the
analog configuration is selected. Selecting the pin as an A/D input disconnects the digital
features of the pin. In that case, the pin value read in register IOPIN is not valid.
Writing to register IOPIN stores the value in the pin output register, bypassing the need to
use both registers IOSET and IOCLR to obtain the entire written value. Use this feature
carefully in an application since it affects all pins.
The slow speed GPIO register is the IO0PIN, while the enhanced GPIOs are supported
via register FIO0PIN. Access to pins via register FIOPIN is conditioned by the
corresponding register FIOMASK (see
).
Table 70.
Fast GPIO mask register (FIO0MASK - address 0x3FFF C010) bit description
Bit
Symbol
Value Description
Reset value
31:0
FP0xMASK
fast GPIO physical pin access control.
0x0000 0000
0
pin is affected by writes to registers FIOSET, FIOCLR, and FIOPIN. Current
state of pin is observable in register FIOPIN.
1
physical pin is unaffected by writes to registers FIOSET, FIOCLR and
FIOPIN. When register FIOPIN is read, this bit is not updated with state of
physical pin
Table 71.
Fast GPIO mask byte and half-word accessible register description
Register
name
Register
length (bits)
and access
Address
Description
Reset
value
FIO0MASK0 8 (byte)
0x3FFF C010
fast GPIO mask register 0. Bit 0 in register FIO0MASK0
corresponds to PIO0 ... bit 7 to PIO7.
0x00
FIO0MASK1 8 (byte)
0x3FFF C011
fast GPIO mask register 1. Bit 0 in register FIO0MASK1
corresponds to PIO8 ... bit 7 to PIO15.
0x00
FIO0MASK2 8 (byte)
0x3FFF C012
fast GPIO mask register 2. Bit 0 in register FIO0MASK2
corresponds to PIO16 ... bit 7 to PIO23.
0x00
FIO0MASK3 8 (byte)
0x3FFF C013
fast GPIO mask register 3. Bit 0 in register FIO0MASK3
corresponds to PIO24 ... bit 7 to PIO31.
0x00
FIO0MASKL 16
(half-word)
0x3FFF C001
fast GPIO mask lower half-word register. Bit 0 in register
FIO0MASKL corresponds to PIO0 ... bit 15 to PIO15.
0x0000
FIO0MASKU 16
(half-word)
0x3FFF C012
fast GPIO mask upper half-word register. Bit 0 in register
FIO0MASKU corresponds to PIO16 ... bit 15 to PIO31.
0x0000