UM10413
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© NXP B.V. 2011. All rights reserved.
User manual
Rev. 1 — 16 December 2011
73 of 268
NXP Semiconductors
UM10413
MPT612 User manual
Aside from the 32-bit long and word-only accessible register FIOCLR, 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 FIOCLR, these additional
registers allow easier and faster access to the physical pins.
13.5 GPIO
usage
notes
13.5.1 Example 1: sequential accesses to IOSET and IOCLR affecting the same
GPIO pin/bit
The state of the output configured GPIO pin is determined by writes into the pin’s port
IOSET and IOCLR registers. The last of these accesses to register IOSET/IOCLR
determines the final output of a pin.
In the case of a code:
IO0DIR = 0x0000 0080 ;pin PIO7 configured as output
IO0CLR = 0x0000 0080 ;PIO7 goes LOW
IO0SET = 0x0000 0080 ;PIO7 goes HIGH
IO0CLR = 0x0000 0080 ;PIO7 goes LOW
Pin PIO7 is configured as an output (write to register IO0DIR). PIO7 output is then set
LOW (first write to register IO0CLR). Short high pulse follows on PIO7 (write access to
IO0SET), and the final write to register IO0CLR sets pin PIO7 back to LOW level.
Table 79.
Fast GPIO output clear register 0 (FIO0CLR - address 0x3FFF C01C) bit description
Bit
Symbol
Description
Reset value
31:0
FP0xCLR
fast GPIO output value clear bits. Bit 0 in FIO0CLR corresponds to PIO0 ... Bit
31 in FIO0CLR corresponds to PIO31.
0x0000 0000
Table 80.
Fast GPIO output clear byte and half-word accessible register description
Register
name
Register
length (bits)
and access
Address
Description
Reset
value
FIO0CLR0
8 (byte)
0x3FFF C01C fast GPIO output clear register 0. Bit 0 in register FIO0CLR0
corresponds to PIO0 ... bit 7 to PIO7.
0x00
FIO0CLR1
8 (byte)
0x3FFF C01D fast GPIO output clear register 1. Bit 0 in register FIO0CLR1
corresponds to PIO8 ... bit 7 to PIO15.
0x00
FIO0CLR2
8 (byte)
0x3FFF C01E
fast GPIO output clear register 2. Bit 0 in register FIO0CLR2
corresponds to PIO16 ... bit 7 to PIO23.
0x00
FIO0CLR3
8 (byte)
0x3FFF C01F
fast GPIO output clear register 3. Bit 0 in register FIO0CLR3
corresponds to PIO24 ... bit 7 to PIO31.
0x00
FIO0CLRL
16
(half-word)
0x3FFF C01C fast GPIO output clear lower half-word register. Bit 0 in register
FIO0CLRL corresponds to PIO0 ... bit 15 to PIO15.
0x0000
FIO0CLRU
16
(half-word)
0x3FFF C01E
fast GPIO output clear upper half-word register. Bit 0 in register
FIO0SETU corresponds to PIO16 ... bit 15 to PIO31.
0x0000