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Philips Semiconductors
ARM-based Microcontroller
GPIO Pin Value Register
(IO0PIN - 0xE0028000, IO1PIN - 0xE0028010, IO2PIN - 0xE0028020, IO3PIN - 0xE0028030)
This register provides the value of the GPIO pins. Register's value reflects any outside world influence on the GPIO configured
pins only. Monitoring of non-GPIO configured port pins using IOPIN register will not be valid, since activities on non-GPIO
configured pins are not indicated in the IOPIN register.
Selection of a single function on a port pin completely excludes all other functions otherwise available on the same pin.
The only partial exception from the above rule of exclusion is in the case of inputs to the A/D converter. Regardless of the function
that is selected for the port pin that also hosts the A/D input, this A/D input can be read at any time and variations of the voltage
level on this pin will be reflected in the A/D readings. However, valid analog reading(s) can be obtained if and only if the function
of an analog input is selected. Only in this case proper interface circuit is active in between the physical pin and the A/D module.
In all other cases, a part of digital logic necessary for the digital function to be performed will be active, and will disrupt proper
behavior of the A/D.
Table 69: GPIO Pin Value Register (IO0PIN - 0xE0028000, IO1PIN - 0xE0028010, IO2PIN - 0xE0028020, IO3PIN -
0xE0028030)
IOPIN
31:0
GPIO pin value bits. Bit 0 in IO0PIN corresponds to P0.0 ... Bit 31 in IO0PIN corresponds to P0.31
GPIO Output Set Register
(IO0SET - 0xE0028004, IO1SET - 0xE0028014, IO2SET - 0xE0028024, IO3SET - 0xE0028034)
This register is used to produce a HIGH level output at the port pins if they are configured as GPIO in an OUTPUT mode. Writing
1 produces a HIGH level at the corresponding port pins. Writing 0 has no effect. If any pin is configured as an input or a secondary
function, writing to IOSET has no effect.
Reading the IOSET register returns the value of this register, as determined by previous writes to IOSET and IOCLR (or IOPIN
as noted above). This value does not reflect the effect of any outside world influence on the I/O pins.
Table 70: GPIO Output Set Register (IO0SET - 0xE0028004, IO1SET - 0xE0028014, IO2SET - 0xE0028024, IO3SET -
0xE0028034)
IOSET
31:0
Output value SET bits. Bit 0 in IO0SET corresponds to P0.0 ... Bit 31 in IO0SET corresponds to P0.31
GPIO Output Clear Register
GPIO
LPC2119/2129/2194/2292/2294
Description
Description
136
Preliminary User Manual
Value after
Reset
Undefined
Value after
Reset
0
May 03, 2004
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