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Table 37 describes the hardware configuration for the operational amplifier interface.
Table 37. Hardware I/O configuration for the operational amplifier interface
I/O Hardware Setting
(1)
Configuration
PA0 SB68
ON PA0 is used as OPAMP1_INP and connected to JP122 pin 3
OFF
PA0 is not used as OpAmp.
PA0 can be used for STMod+, UCPD, or motor control.
OPAMP1_INM _ -
OPAMP1_INM dedicated pin is used as OPAMP1_INM and
connected to R44 / RV2.
PA3 SB53
ON PA3 is used as OPAMP1_VOUT and connected to TP18.
OFF
PA3 is not used as OpAmp.
PA3 can be used for Octo
‑
SPI or motor control.
1. The default configuration is shown in bold.
The non-inverting input PA0 is accessible on JP22 jumper header pin 3. On top of the possibility of routing, either
of the potentiometer or LDR to PA0, an external source can also be connected to it, using JP22 terminal 3.
The PA3 output of the operational amplifier can be accessed on the TP18 test point. Refer to the schematic of the
STM32U575I-EV Evaluation board.
The gain of OpAmp1 is determined by the ratio of the variable resistor RV2 and the resistor R44, as shown in the
following equation:
Gain = 1 + RV2
R44
With the RV2 ranging from 0 to 10 kΩ and R44 being 1 kΩ, the gain can vary from 1 to 11.
The R39 resistor in series on PA0 is beneficial for reducing the output offset.
Table 38 describes the jumper configuration to enable the LDR or the potentiometer to the OpAmp1 function.
Table 38. Jumper configuration to enable the LDR or the potentiometer to the OpAmp1 function
Hardware Setting
(1)
Configuration
JP21 / JP22
JP21[1-2] /
JP22[2-3]
Potentiometer is routed to the OPAMP1_INP PA0 pin of STM32U575AII6Q.
JP21[2-3] /
JP22[2-3]
LDR is routed to the OPAMP1_INP PA0 pin of STM32U575AII6Q.
1. The default configuration is shown in bold.
7.20.4 Comparator
STM32U575AII6Q provides two onboard comparators. One of which, Comp2, is made accessible on the
STM32U575I-EV Evaluation board. Comp2 has its non-inverting input and its output.
Table 39 describes the hardware configuration for the comparator interface.
STM32U575I-EV
Operational amplifiers and comparator
UM2854 - Rev 1
page 53/105