UM10503
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© NXP B.V. 2012. All rights reserved.
User manual
Rev. 1.3 — 6 July 2012
297 of 1269
NXP Semiconductors
UM10503
Chapter 15: LPC43xx System Control Unit (SCU)/ IO configuration
By default, all pins are connected to their digital function 0 and only the digital pad is
available.
To select the analog function, the pad must be set as follows using the corresponding
SFSP register:
1. Tri-state the output driver by selecting an input at the pinmux e.g. GPIO function in
input mode.
2. Disable the receiver by setting the EZI bit to zero (see
or
the default setting.
3. Disable the pull-up resistor by setting the EPUN bit to one, and disable the pull-down
resistor by setting the EPD bit to zero.
4. Set the bit corresponding to the analog function to 1 in the ENAIO0 register.
Table 138. Pins controlled by the ENAIO0 register
Pin
ADC function
ENAIO0 register bit
P4_3
ADC0_0
0
P4_1
ADC0_1
1
PF_8
ADC0_2
2
P7_5
ADC0_3
3
P7_4
ADC0_4
4
PF_10
ADC0_5
5
PB_6
ADC0_6
6
Table 139. ADC0 function select register (ENAIO0, address 0x4008 6C88) bit description
Bit
Symbol
Value Description
Reset
value
Access
0
ADC0_0
Select ADC0_0
0
R/W
0
Digital function selected on pin P4_3.
1
Analog function ADC0_0 selected on pin P4_3
1
ADC0_1
Select ADC0_1
0
R/W
0
Digital function selected on pin P4_1.
1
Analog function ADC0_1 selected on pin P4_1.
2
ADC0_2
Select ADC0_2
0
R/W
0
Digital function selected on pin PF_8.
1
Analog function ADC0_2 selected on pin PF_8.
3
ADC0_3
Select ADC0_3
0
R/W
0
Digital function selected on pin P7_5.
1
Analog function ADC0_3 selected on pin P7_5.
4
ADC0_4
Select ADC0_4
0
R/W
0
Digital function selected on pin P7_4.
1
Analog function ADC0_4 selected on pin P7_4.
5
ADC0_5
Select ADC0_5
0
R/W
0
Digital function selected on pin PF_10.
1
Analog function ADC0_5 selected on pin PF_10.