Understanding STM32 Sub-families

[Justin1]

I have selected the STM32F091RCT for a new design and was having trouble understanding a specific section of the naming schema -

Example: STM32F091RCT

Sub-family: '91'

• 0: Value line
• 1: Access line
• 2: USB line
• 8: Low-voltage line

The '1' makes sense this is the access line, as described in the Datasheet's Ordering Information. What is the '9' though? Is there a reference explaining this item?

[waclawek.jan]

There's no strict logic in this, the middle digit here simply increases with increasing chip size/number of implemented peripherals.

JW

[Khouloud GARSI]

Hi @Justin​ ,

As indicated in the Datasheet section Ordering information, the STM32F091RCT:

• STM32 = ARM-based 32-bit microcontroller 
• F = General-purpose 
• 091= STM32F091xx 
• R = 64 pins 
• C = 256 Kbyte
• T = LQFP  

To have more details about the features and peripherals supported by your device, you may have a look on table "STM32F091xB/xC family device features and peripheral counts".

Link to the datasheet:

https://www.st.com/resource/en/datasheet/dm00115237.pdf

Khouloud.