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.

[STTwo-32 · Accepted solution]

Hello @rohithinthingstech 

For the questions about the Pins that are not available on the STM32WL55CC, you can refer to the DS13293. For the reference designs, you can refer to one of the designs dedicated to the UFQFPN package on this table:

Best Regards.

STTwo-32