Topic : STM32F105 (and F107) have wrong RAM Size

Forum : ARM

Original Post
Post Information Post
July 16, 2018 - 6:31pm
Timothy Burbridge

When selecting target Processor, STM32F105x8 and STM32F107x8 show 20K RAM. STM32F105xB, STM32F107xB show 32K RAM.

The documentation shows that all processors of Line STM32F105xx and STM32F107xx have 64K RAM (See The first page of the data sheet declares a set 64K, and page 94 "Part Numbering" shows that the second letter of '8', 'B', or 'C' are for FLASH sizes, not RAM.

Found this out when Debugging a STM32F105VBT6, and the memory viewer didn't show anything above 0x20007FFF (32K of RAM).

The STM32F105xC and STM32F107xC show 64K RAM, but the other ones are wrong.


Timothy Burbridge