Limitations; Operational Amplifier And Comparator; Operational Amplifier; Table 15. Port Assignment For Control Of Physical Input Devices - ST STM32G474E-EVAL User Manual

Hardware layout and configuration
Jumper
JP5
5.15.1

Limitations

The potentiometer and the light-dependent resistor are exclusive to high-brightness LED
and MC operation. And they are mutually exclusive.
5.16

Operational amplifier and comparator

5.16.1

Operational amplifier

STM32G474QET6 provides an on-board operational amplifier, OpAmp4, which is made
accessible on STM32G474E-EVAL. OpAmp4 has its inputs and output routed to I/O ports
PB11, PB10, and PB12, respectively.
The PB12 output of the operational amplifier can be accessed on test point TP2. Refer to
the schematic diagrams.
The ratio of the variable resistor RV1 and the resistor R157 determines the gain of OpAmp4,
as shown in the following equation:
With the RV1 ranging from 0 to 10 kΩ and R157 being 1 kΩ, the gain can vary from 1 to 11.
The R158 resistor in series with PB12 is beneficial for reducing the output offset.
Table 16
function.
Element
SB11
SB71
34/66

Table 15. Port assignment for control of physical input devices

setting
1 2 3
1 2 3
shows the configuration elements and their settings to access the OpAmp4

Table 16. Configuration elements related to OpAmp4

Setting
SB11 ON
SB71 OFF
SB11 OFF
SB71 ON
Default setting.
The potentiometer is routed to pin PB11 of
STM32G474QET6.
LDR is routed to pin PB11 of STM32G474QET6.
Gain = 1+ RV1/R157
Default setting.
Pin PB10 of STM32G474QET6 is routed to OpAmp4_VINM.
Pin PB10 of STM32G474QET6 is routed to OpAmp4_INN of MC.
UM2514 Rev 5
Routing
Configuration
UM2514