Migrating from STM32WL55JC17 (UFBGA) to STM32WL55CC (UFQFPN) – Missing Pin Equivalents

[rohithinthingstech]

Hello STM32 Community,

I'm working on a custom board based on the MB1389 (Nucleo-WL55JC) reference design, which uses the STM32WL55JC17 (UFBGA) package. Now, I am migrating to the STM32WL55CC in the UFQFPN package for cost and space reasons.

While adapting the schematic, I noticed the following pins from the original design are not available in the UFQFPN package:

• PC3

• PC4

• PC5

• PB14

• PB1

• VSSRF

• VREF+

I understand that the pin count is reduced in the UFQFPN package, but I need guidance on the following:

1. Are there any internal remapping or alternative GPIOs for the above functions in the STM32WL55CC UFQFPN package?

2. How should I handle VSSRF and VREF+, since they are critical for RF and analog operations? Can they be connected internally, or do they need external routing?

3. Any advice or reference designs (for UFQFPN-based layouts) that clarify how to proceed with features that originally used those missing pins?

For reference, I am attaching a snippet of my schematic based on MB1389, where these pins are currently used.

[ahsrabrifat]

Use STM32CubeMX or STM32CubeIDE to remap peripherals or GPIO functionality to available pins. Many peripheral functions (SPI, I2C, UART, ADC, etc.) are available on multiple pins.