ST STM32 Series Installation and operating instructions

July 2011 Doc ID 018608 Rev 1 1/12

AN3364

Application note

Migration and compatibility guidelines

for STM32 microcontroller applications

1 Introduction

For designers of STM32 microcontroller applications, it is important to be able to easily

replace one microcontroller type by another one in the same product series. 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. On the other

hand, cost reduction objectives may force you to switch to smaller components and shrink

the PCB area. This application note is written to help you and analyze the steps you need to

migrate from an existing STM32-based design to any one of the other microcontroller types

in the fast-growing STM32 series.

To save your time, this application note groups together all the most important information

and lists the vital aspects that you need to address.

All the information included here can also be extremely worthwhile in your first STM32

design, not immediately concerned by a migration project. Studying the issues now will help

you tackle any future requirement by designing for compatibility from the beginning. To use

this application note, general STM32 knowledge is required, you can learn it from the

STM32 series reference manual, the STM32 datasheets, and the STM32 Flash program

memory programming manuals.

This application note presents an overview of the whole STM32 series and presents a first

level view of the different aspects that are important to consider when planning a new design

or migrating. The microcontroller blocks and peripherals are grouped and identified either as

fully compatible or compatible with enhancements or presented by types of series.

However the details of the migration guidelines across STM32 series are documented in

separate documents. Please refer to either of the following two documents:

●AN3427 Migrating applications from STM32F1 series to STM32F2 series

●AN3422 Migrating applications from STM32F1 series to STM32L1 series.

www.st.com

Contents AN3364

2/12 Doc ID 018608 Rev 1

Contents

1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

2 How to migrate across STM32 series . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.1 STM32 series general overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

2.1.1 STM32 product series feature comparison . . . . . . . . . . . . . . . . . . . . . . . 4

2.1.2 STM32 product cross-compatibility . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

2.2 Software migration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

3 Revision history . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

AN3364 How to migrate across STM32 series

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2 How to migrate across STM32 series

2.1 STM32 series general overview

The STM32 platform forms a strong foundation with a broad and growing portfolio. With new

products addressing new applications, the complete STM32 product series now comprises

three series, STM32F-1, STM32F-2 and STM32L-1, each dedicated to a specific segment:

●STM32 F-1:The general-purpose F-1 series addresses a wide range of applications,

from the lowest, price-sensitive designs to computing-intensive, high memory footprint

ones.

The F-1 series is a complete series whose members are fully pin-to-pin, software and

feature compatible.

–Low-density devices are STM32F101xx and STM32F103xx microcontrollers

where the Flash memory density ranges between 16 and 32 Kbytes.

–Medium-density devices are STM32F101xx and STM32F103xx microcontrollers

where the Flash memory density ranges between 32 and 128 Kbytes.

–High-density devices are STM32F101xx and STM32F103xx microcontrollers

where the Flash memory density ranges between 256 and 512 Kbytes.

– XL-density devices are STM32F101xx and STM32F103xx microcontrollers where

the Flash memory density ranges between 768 Kbytes and 1024 Kbyte.

–Connectivity-line devices are STM32F105xx and STM32F107xx microcontrollers

where the Flash memory density ranges between 64 and 256 Kbytes.

–Medium-density value line device is STM32F100xx microcontrollers where the

Flash memory density ranges between 64 and 128 Kbytes

–High-density value line device is STM32F100xx microcontrollers where the

Flash memory density ranges between 128 and 512 Kbytes.

●STM32 F-2:The F-2 series provides the highest performance for computing-intensive

applications and advanced connectivity. The F2 series maintains compatibility with the

F1 series.

●STM32 L-1: Designed for ultra-low-power applications that are energy-aware and seek

to achieve the absolute lowest power consumption. The L-1 series maintains

compatibility with the F1 series.

In the rest of this document (unless otherwise specified),

– the terms F1, STM32 F1 and STM32F10x are used to refer to the STM32 F-1

series

– the terms F2, STM32 F2 and STM32F2xx are used to refer to the STM32 F-2

series

– the terms L1, STM32 L1 and STM32L1xx are used to refer to the STM32 L-1

series

How to migrate across STM32 series AN3364

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2.1.1 STM32 product series feature comparison

Table 1. STM32 series overview

Peripheral STM32 F-1 Series STM32 L-1 Series STM32 F-2 Series

Core Cortex-M3 r1p1

MPU in XL-density only Cortex-M3 r2p0 w/ MPU Cortex-M3 r2p0 w/ MPU

FLASH memory 16 / 32 / 64 / 128 / 256 / 384 /

512 / 768KB - 1 MB 64/128 KB 128 / 256 / 512 / 768 /

1024 KB

SRAM 6 / 10 / 20 / 24 / 32 / 48 / 64 /

96 KB 10/16 KB

64/96/128 KB

+ 4KB backup SRAM

(can be used as

EEPROM memory)

OTP No No Yes (512 Bytes)

FSMC Ye s N o Ye s

Max CPU frequency

24 / 36 / 48 / 72 MHz

depending on the product

line used

32 MHz 120 MHz

Operating voltage 2.0 to 3.6 V 1.65 to 3.6 V 1.8(1) to 3.6 V

Bootloader (2)

Connectivity Line:

USART1/2, CAN2, DFU

(OTG FS Device)

Other product lines: USART1

USART1/2 USART1/3, CAN2, DFU

(OTG FS Device)

Timers

Advanced up to 2 No 2

General purpose up to 4 3 4

Basic up to 2 2 2

2 Channels up to 2 1 2

1 Channel up to 4 2 4

RTC Counter Hardware calendar Hardware calendar

COMs

SPI(I2S) up to 3(2) 2 3(2)

TI mode No No Yes

Max freq up to 18 Mbits/s up to16 Mbits/s up to 15 or 30 Mbits/s

Audio freq 8 kHz up to 96 kHz No 8 kHz up to 192 kHz

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COMs

I2C up to 2 2 3

Max freq 400 KHz 400 KHz 400 KHz

USART up to 3 3 4

UART up to 2 No 2

Max baud rate 2.25 or 4.5 Mbit/s up to 4 Mbit/s 3.75 or 7.5 Mbit/s

USB USB Device FS USB Device FS OTG FS

OTG FS OTG HS

CAN up to 2 No 2

SDIO 1No1

CEC up to 1 No No

Ethernet MAC Yes w/ HW IEEE 1588 v1 No Yes w/ HW IEEE1588 v2

GPIOs 26/37/51/80/112 37/51/83 51/82/114/140

12 bit ADC up to 3 1 3

Max Sampling freq 1 MSPS 1 MSPS 2 MSPS

Number of channels 10/16/21 channels 16/20/24 channels 16/24 Channels

12 bit DAC 222

Max Sampling freq 1 MS/s 1 MS/s 1 MS/s

Number of channels 222

DCMI No No Yes

Crypto/hash processor No No

Ye s

DES, 3DES, AES 256-bit

SHA-1, MD5, HMAC

Table 1. STM32 series overview (continued)

Peripheral STM32 F-1 Series STM32 L-1 Series STM32 F-2 Series

How to migrate across STM32 series AN3364

6/12 Doc ID 018608 Rev 1

RNG No No Yes

Package

VFQFPN36

LQFP48 LQFP48

VFQFPN48 VFQFN48

LQFP64 LQFP64 LQFP64

BGA64

WLCSP64 WLCSP64

TFBGA64

LQFP100 LQFP100 LQFP100

BGA100 BGA100

LFBGA100

LQFP144 LQFP144

BGA144

UFBGA176

1. If IRROFF is set to VDD on STM32F20xx devices, this value can be lowered to 1.65 V when the device operates in a

reduced temperature range.

2. For more information, please refer to application note AN2606 STM32 microcontroller system memory boot mode.

Table 1. STM32 series overview (continued)

Peripheral STM32 F-1 Series STM32 L-1 Series STM32 F-2 Series

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2.1.2 STM32 product cross-compatibility

The STM32 series embeds a set of peripherals which can be classed in three categories:

●The first category is for the peripherals which are by definition common to all products.

Those peripherals are identical, so they have the same structure, registers and control

bits. There is no need to perform any firmware change to keep the same functionality at

the application level after migration. All the features and behavior remain the same.

●The second category is for the peripherals which are shared by all products but have

only minor differences (in general to support new features), so migration from one

product to another is very easy and does not need any significant new development

effort.

●The third category is for peripherals which have been considerably changed from one

product to another (new architecture, new features...). For this category of peripherals,

migration will require new development at application level.

Table 2 below gives a general overview of this classification:

Table 2. STM32 peripheral compatibility analysis F1 versus F2 series

Peripheral F1 series F2 series

Compatibility

Comments Pinout SW compatibility

FSMC Yes Yes Same features Identical Full compatibility

WWDG Ye s Yes Same features NA Full compatibility

IWDG Ye s Yes Same features NA Full compatibility

DBGMCU Ye s Yes Same features NA Full compatibility

CRC Ye s Yes Same features NA Full compatibility

EXTI Ye s Yes Same features Identical Full compatibility

CAN Ye s Yes Same features Identical Full compatibility

PWR Ye s Ye s + Enhancement NA Full compatibility for

the same feature

RCC Ye s Ye s + Enhancement NA Partial compatibility

SPI Ye s Ye s + TI mode / Max baudrate Identical Full compatibility for

the same feature

USART Ye s Ye s +

Limitation fix / Max baudrate /

One Sample Bit / Oversampling

by 8

Identical Full compatibility for

the same feature

I2C Ye s Ye s + Limitation fix Identical Full compatibility for

the same feature

TIM Ye s Ye s + 32-bit Counter in TIM2 and

TIM5 Identical Full compatibility for

the same feature

DAC Ye s Ye s + DMA underrun interrupt Identical Full compatibility for

the same feature

How to migrate across STM32 series AN3364

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Ethernet Ye s Ye s + IEEE1588 v2 / Enhanced DMA

descriptor Identical Full compatibility for

the same feature

SDIO Ye s Ye s + Limitation fix Identical Full compatibility for

the same feature

USB OTG FS Ye s Ye s +

- Dynamic trimming capability of

SOF framing period in Host

mode

- Embeds a VBUS sensing

control

Identical Full compatibility for

the same feature

RTC Ye s Yes++ New peripheral Identical for the

same feature Not compatible

ADC Ye s Yes++ New peripheral Identical for the

same feature Partial compatibility

FLASH Ye s Yes++ New peripheral NA Not compatible

DMA Ye s Yes++ New peripheral NA Not compatible

GPIO Ye s Yes++ New peripheral Identical Not compatible

CEC Ye s NA NA NA NA

USB FS

Device Ye s NA NA NA NA

Crypto/hash

processor NA Ye s NA NA NA

RNG NA Ye s NA NA NA

DCMI NA Ye s NA NA NA

USB OTG HS NA Ye s NA NA NA

SYSCFG NA Ye s NA NA NA

Table 2. STM32 peripheral compatibility analysis F1 versus F2 series (continued)

Peripheral F1 series F2 series

Compatibility

Comments Pinout SW compatibility

Color key:

= New feature or new architecture (Yes++)

= Same feature, but specification change or enhancement (Yes+)

= Feature not available (NA)

AN3364 How to migrate across STM32 series

Doc ID 018608 Rev 1 9/12

Table 3. STM32 peripheral compatibility analysis F1 versus L1 series

Peripheral F1 series L1 series

Compatibility

Comments Pinout SW compatibility

SPI Ye s + Ye s No I2S in L1 series

L1 vs. F1: limitation fix Identical Full compatibility

WWDG Ye s Yes Same features NA Full compatibility

IWDG Ye s Yes Same features NA Full compatibility

DBGMCU Ye s Yes Same features NA Full compatibility

CRC Ye s Yes Same features NA Full compatibility

EXTI Ye s Yes Same features Identical Full compatibility

USB FS

Device Ye s Yes Same features Identical Full compatibility

DMA Ye s Yes Same features NA Full compatibility

TIM Ye s Yes Same features Identical Full compatibility

PWR Ye s Ye s + Enhancement NA Full compatibility for the

same feature

RCC Ye s Ye s + Enhancement NA Partial compatibility

USART Ye s Ye s +

Limitation fix / One Sample

Bit method / Oversampling by

Identical Full compatibility

I2C Ye s Ye s + Limitation fix Identical Full compatibility

DAC Ye s Ye s + DMA underrun interrupt Identical Full compatibility

ADC Ye s Yes++ New peripheral Identical Partial compatibility

RTC Ye s Yes++ New peripheral Identical for the

same feature Not compatible

FLASH Ye s Yes++ New peripheral NA Not compatible

GPIO Ye s Yes++ New peripheral Identical Not compatible

CAN Ye s NA NA NA NA

CEC Ye s NA NA NA NA

Ethernet Ye s NA NA NA NA

SDIO Ye s NA NA NA NA

FSMC Ye s NA NA NA NA

LCD glass NA Ye s NA NA NA

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2.2 Software migration

Each STM32 series is supported by a complete range of high-end and low-cost evaluation,

software, debugging and programming tools.

This complete line includes third-party solutions that come complete with an integrated

development environment and in-circuit debugger/programmer featuring a JTAG application

interface. Developers who are new to this series and the Cortex™ core can also benefit from

the range of starter kits that are specially designed to help developers evaluate device

features and start their own applications.

Thanks to ST firmware libraries and a comprehensive set of application notes, STM32

microcontrollers offer a complete software interface to reduce the time to market and keep

the user code independent from hardware details. The state-of-the-art and highly efficient

library of software drivers combined with extensive support for all major tool providers offers

a fast route to best-fit and an optimized development process.

COMP NA Yes NA NA NA

SYSCFG NA Yes NA NA NA

Table 3. STM32 peripheral compatibility analysis F1 versus L1 series (continued)

Peripheral F1 series L1 series

Compatibility

Comments Pinout SW compatibility

Color key:

= New feature or new architecture (Yes++)

= Same feature, but specification change or enhancement (Yes+)

= Feature not available (NA)

This manual suits for next models

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