RM0444 Rev 5 239/1390
RM0444 General-purpose I/Os (GPIO)
247
Figure 20. Alternate function configuration-
7.3.12 Analog configuration
When the I/O port is programmed as analog configuration:
• The output buffer is disabled
• The Schmitt trigger input is deactivated, providing zero consumption for every analog
value of the I/O pin. The output of the Schmitt trigger is forced to a constant value (0).
• The weak pull-up and pull-down resistors are disabled by hardware
• Read access to the input data register gets the value “0”
Figure 21 shows the high-impedance, analog-input configuration of the I/O port bits.
Figure 21. High impedance-analog configuration
MSv31479V2
Output
control
Output data register
Bit set/reset registers
Input data register
Read
To/from on-chip
peripheral
Analog input/output
P-MOS
Output driver
V
DDIOx
V
SS
N-MOS
Push-pull
or open-drain
V
SS
V
DDIOx
on/off
on/off
I/O pin
TTL Schmitt trigger
On
Write
Read/write
Pull
up
Pull
down
Input driver
Alternate function input
Alternate function output
From on-chip
peripheral
MSv33185V2
Output data register
Bit set/reset registers
Input data register
Read
To/from on-chip
peripheral
Analog input/output
Output driver
I/O pin
TTL Schmitt trigger
Off
Write
Read/write
Input driver
0
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