Artery AT32F403A as an STM32F103 Replacement: Migration Effort and Cost Case

The STM32F103 is one of the most widely used microcontrollers ever shipped, which means a very large number of boards in the field are built around it. When supply or price moves, the first question engineering asks is whether a drop-in alternative exists. The Artery AT32F403A is the part that comes up most often in that conversation. This article covers both halves of the decision: what it takes to migrate, and what the migration is worth in cost terms.

Why the F103 replacement conversation happens

Two triggers push projects to look for an alternative. The first is availability: a legacy part goes on allocation or a long allocation, and a production line that cannot ship is a much bigger cost than any component delta. The second is unit cost at a volume where the original part's price is no longer competitive. Both are valid reasons, and both are answered differently, so it is worth naming which one you are solving before you start.

Pin-level compatibility: what to check first

The AT32F403A is offered in the same common LQFP packages used by the F103, so the physical swap is not the hard part. The checks that matter are:

Run the comparison on a test board using your own layout before you commit. A one-week bench comparison is cheaper than a re-spin.

Firmware porting: a realistic budget

The register names are close enough that porting is normally described as a project re-point rather than a rewrite. In practice the effort concentrates in three places: the clock tree configuration, the flash wait-state setting for the core frequency you want, and anything that assumes the original bootloader's vector placement. For a moderate firmware this is a week of engineering, not a month. Keep the original tree in your repository until the first production batch has shipped, because the fallback path is worth more than the cleanliness of the history.

The cost case, item by item

Here is the comparison we run with customers, in the order we think about it:

The naive comparison is the first row. The honest comparison is the sum of all six. Projects that win the argument are the ones where the silicon delta is large enough, or the availability risk is sharp enough, to repay the porting week quickly.

Where the F403A sits in the wider AT32 range

If you are already migrating, it is worth asking whether the target is the right target. The AT32F403A is a mainstream part aimed squarely at the general-control slot. If your firmware fits comfortably in less flash than the F103 variant you use today, the entry tier may be a better destination and a cheaper one: AT32F413RBT7 and AT32F415CBT7 are both mainstream parts with a different cost profile.

Other mainstream parts in the same family, if you are re-spinning the board anyway:

AT32F403ARGT7 · AT32F405CCT7 · AT32F407VET7 · AT32F413CBT7

Related reading

Microcontrollers and MCUs · AT32F403ARCT7 · AT32F403ERPT7

Frequently asked questions

Is the AT32F403A really pin compatible with the STM32F103?

At the pin level, yes for the common LQFP48 and LQFP64 packages in the standard ordering, which is why migration projects start from a re-layout check rather than a new board. electrically you still need to verify three things: the decoupling and reset pin definitions, the boot mode pin configuration, and the oscillator start-up behaviour. Boot mode handling in particular differs, so keep the boot strapping pins on the first revision even if you think the firmware sets them internally.

What code changes are needed when moving to the AT32F403A?

The peripheral register names are broadly similar, so most of the work is re-pointing the project at the Artery device support package and the AT32 SDK rather than rewriting drivers. The usual pain points are the clock tree configuration, the flash wait-state setting at high core frequencies, and any code that assumes the exact reset vector placement. Budget a porting week for an existing STM32F103 firmware of moderate size, and keep the STM32 tree around until the first production batch ships.

What is the cost argument for the migration?

The saving shows up on the whole BOM, not only on the MCU line. In typical quotes we see the MCU position improve materially at volume, and the board often gets cheaper as well because the AT32F403A integrates more flash than the part it replaces, which lets some designs drop an external EEPROM. Whether the migration pays back depends on your volume and on how much engineering time you can absorb, so treat the silicon delta as one input and the porting cost as another.

Will an AT32F403A drop into an existing STM32F103 footprint without board changes?

Sometimes. The safer path is to order one of each, put both on a test board using your existing layout, and compare power-on behaviour, ADC readings and thermal. We supply both the LQFP48 and LQFP64 variants in small quantities specifically so engineers can run this comparison before committing to a re-spin.

What should I check before placing a volume order?

Confirm the package and temperature grade against your product's operating range, confirm the flash density matches the firmware you will ship in year three, and check the long-lead position for your chosen package. Ask your supplier for the production status and the recommended last-time-buy date before you design it in, not after.

About us & trademarks: JTDZ Tech (Shenzhen Jingteng Electronics Technology Co., Ltd.) is an independent distributor of electronic components. We are not an authorised distributor or representative of the manufacturers named in this article. Manufacturer and part names are used for indicative purposes only, to help identify the components discussed; all trademarks remain the property of their respective owners. Always verify specifications against the official datasheet before design-in or purchase.