I'm currently using the STM32F051R8T6, 64 pin LQFP. Is the STM32F091RCT6 in the same package fully pin-compatible?
No, those two products are not fully pin to pin compatible.
I advise you to download their datasheets and see the pinout differences on section "Pinouts and pin descriptions".
If this answers your request, please press "correct" .
Thanks. I looked at the pinout of the package I need, and found that they're close. PF5, PF6, PF7 are VSS/VDD pins on the '091. I only use Ports A/B/C, so with a simple board change, I can switch to this part, and get 4x the RAM. That should work out just fine.
Do not forget to connect the new VDD/VDDIO2/VSS pins.
And, your migtation to STM32F091 should be fine.
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