Analog Configuration; Figure 15. Alternate Function Configuration - ST STM32F100 Series Reference Manual

General-purpose and alternate-function I/Os (GPIOs and AFIOs)
Alternate Function Input
To on-chip
peripheral
Read
Write
Read/write
From on-chip
Alternate Function Output
peripheral
1. V is a potential specific to 5-Volt tolerant I/Os, and different from V
DD_FT
7.1.10

Analog configuration

When the I/O Port is programmed as Analog configuration:
•
The Output Buffer is disabled.
•
The Schmitt Trigger Input is de-activated 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.
•
Read access to the Input Data register gets the value "0".
Figure 16
108/709

Figure 15. Alternate function configuration

Input driver
Output driver
shows the high impedance-analog configuration of the I/O Port bit.
on
TTL Schmitt
trigger
V
DD
Output
control
V
SS
.
DD
RM0041 Rev 6
V
P-MOS
VSS
N-MOS
push-pull or
open-drain
RM0041
(1)
or V
DD DD_FT
Protection
diode
I/O pin
Protection
diode
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