Does the STM32L552CC with 256 kB flash have a dual bank flash? The product selector says "yes", but the data sheet and the reference manual only mention the 512 kB variant (STM32L552CE).

[ChahinezC]

Hello @dost​,

As per the STM32L552xx datasheet, the Flash interface features are as follows:

• Single or dual bank operating modes
• Read-while-write (RWW) in dual bank mode

And referring to the RM0438, the Flash memory has the following main features:

• Capacity up to 512 Kbytes, in single-bank mode (read width of 128 bits) or in dual-bank mode (read width of 64-bits).
• Dual-bank mode when DBANK bit is set: – 256 Kbytes organized in two banks for main memory. – Page size of 2 Kbytes. – 72 bits wide data read (64 bits plus 8 ECC bits). – Bank and mass erase.
• Single-bank mode when DBANK is reset: – 512 Kbytes organized in one single bank for main memory. – Page size of 4 Kbytes. – 144 bits wide data read (64 bits plus 2x 8 ECC bits). – Mass erase

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Chahinez.

[dost]

Hallo @ChahinezC​ ,

thank you for your answer, but just copying the datasheet and reference manual isn't helpful. It just says, that the capacity is up to 512 Kbytes and it can be organized in dual-bank mode with 2x256 Kbytes.

For the STM32L552CE with its flash size of 512 Kbytes it's all clear.

But what is with the STM32L552CC with a total flash size of just 256 Kbytes? Does it have just one bank with 1x256 Kbytes oder two with 2x128 Kbytes? There should be more information in the reference manual, the STM32L552CC variant isn't mentioned at all.

Best regards,

Markus

[ChahinezC · Accepted solution]

Hello @dost​,

• Yes, in the STM32L552CE, same as STM32L552CC, the Flash interface features can be operating either in single or dual bank mode.

• Whatever the part number flash memory size is, 512K or 256K, to work in dual bank mode, DBANK option bit must be 1. 
• Then if you are in single mode (DBANK = 0), for a part number 256KB, the DB256 bit must be 0.
• And if you are in dual bank mode, for a 256KB part number, DB256 must be at 1 to have always bank1/bank2 each 128KB contiguous.

• For the documentation part, thank you for reproducing it, I will report it internally in order to add the concerned parts.

Chahinez.

[ChahinezC]

Internal ticket number: 123359.

This is an internal tracking number and is not accessible or usable by customers.

Thank you.