Introduction

For designers of STM32 microcontroller applications, the ability to easily replace one microcontroller type with another from the

same product family is an important asset.

Migrating an application to a different microcontroller is often needed when product requirements grow, putting extra demands

on memory size or increasing the number of I/Os. Cost reduction objectives may also be a reason to switch to smaller

components and shrink the PCB area.

This application note analyses the steps required to migrate an existing design between STM32F303/F334 lines and

STM32G431xx/G474xx/G491xx microcontrollers. All the most important information is grouped here. Three aspects need to

be considered for the migration: the hardware, peripheral(s) and firmware.

This document lists the full set of features available for STM32F303/F334 lines and the equivalent features on STM32G431xx/

G474xx/G491xx devices.

To fully benefit from this application note, the user should be familiar with the STM32 microcontroller documentation available on

www.st.com with a particular focus on:

• STM32F3 reference manuals:

– STM32F303xB/C/D/E, STM32F303x6/8, STM32F328x8, STM32F358xC, STM32F398xE advanced Arm

-based

MCUs (RM0316)

– STM32F334xx advance Arm

-based 32-bit MCUs (RM0364)

• STM32F3 datasheets:

– STM32F303xB STM32F303xC datasheet

– STM32F303xD STM32F303xE datasheet

– STM32F303x6/x8 datasheet

• STM32G4xx reference manuals:

– STM32G4xx advanced Arm

-based 32-bit MCUs (RM0440)

• STM32G431xx/G474xx/G491xx datasheets

Table 1. Applicable products

Type Product lines and part numbers

Microcontrollers

STM32F3xx

STM32F303 Lines

STM32F334 Lines

STM32G431xx

STM32G431C6, STM32G431C8, STM32G431CB, STM32G431K6, STM32G431K8, STM32G431KB,

STM32G431M6, STM32G431M8, STM32G431MB, STM32G431R6, STM32G431R8, STM32G431RB,

STM32G431V6, STM32G431V8, STM32G431VB

STM32G474xx

STM32G474CB, STM32G474CC, STM32G474CE, STM32G474MB, STM32G474MC, STM32G474ME,

STM32G474QB, STM32G474QC, STM32G474QE, STM32G474RB, STM32G474RC, STM32G474RE,

STM32G474VB, STM32G474VC, STM32G474VE

STM32G491xx

STM32G491CC, STM32G491CE, STM32G491KC, STM32G491KE, STM32G491MC, STM32G491ME,

STM32G491RC, STM32G491RE, STM32G491VC, STM32G491VE

Migrating between STM32F334/303 lines and STM32G431xx/G474xx/G491xx

microcontrollers

AN5094

Application note

AN5094 - Rev 4 - September 2021

For further information contact your local STMicroelectronics sales office.

www.st.com

1 STM32G431xx/G474xx/G491xx overview

The STM32G431xx/G474xx/G491xx are based on the high-performance Arm

Cortex

-M4 32-bit, up to 170 MHz

and include a larger set of peripherals with advanced features compared to the STM32F303 lines ones, such as:

• Advanced encryption hardware accelerator (AES)

• Serial audio interface (SAI)

• Low-power UART (LPUART)

• Low-power timer (LPTIM)

• Voltage reference buffer (VREFBUF)

• Quad-SPI interface (QUADSPI)

• Clock recovery system (CRS) for USB

• SRAM1 size is different on the various STM32G431xx/G474xx/G491xx devices:

– 16 Kbytes for STM32G431xx

– 80 Kbytes for STM32G474xx

– 80 Kbytes for STM32G491xx

• Additional SRAM2 with data preservation in Standby mode:

– 6 Kbytes for STM32G431xx

– 16 Kbytes for STM32G474xx

– 16 Kbytes for STM32G491xx

• CCM SRAM :

– 10 Kbytes for STM32G431xx

– 32 Kbytes for STM32G474xx

– 16 Kbytes for STM32G491xx

• 8-bit ECC on FLASH memory

• Dual bank boot (only on STM32G474xx)

This migration guide is only covering the migration from STM32F303/F334 lines to STM32G431xx/G474xx/

G491xx devices. As a consequence the new features present on STM32G431xx/G474xx/G491xx but not already

present on STM32F303 lines are not covered (refer to the STM32G431xx/G474xx/G491xx devices reference

manuals and datasheets for an exhaustive overview).

This document applies to STM32F334/303 lines and STM32G431xx/G474xx/G491xx Arm

-based devices.

Note: Arm is a registered trademark of Arm Limited (or its subsidiaries) in the US and/or elsewhere.

AN5094

STM32G431xx/G474xx/G491xx overview

AN5094 - Rev 4

page 2/36