stm32F105RB flash range

[Treacy Yao]

Posted on July 09, 2018 at 09:45

Hello,

I have stm32F105RB with 128KB flash and 64KB sram. But I qury the related document, the flash organization is as below which total flash size is 256KB. Are there any other documents to introduce the 128KB flash of 

stm32F105RB

? My undestanding of  

stm32F105RB with 128KB flash

address is 0x08000000-?0x0801FFFF,0x08020000-0x01FFFAFFF is reserved. Am I right?#stm32f105rb-flash

[AvaTar]

Posted on July 09, 2018 at 10:41

But I qury the related document, the flash organization is as below which total flash size is 256K.

Not sure what you mean.

Check the datasheet, downloadable here :

https://www.st.com/en/microcontrollers/stm32f105rb.html

 

Page 33 has a mamory map, with Flash from 08000000 - 0803FFFF.

[Treacy Yao]

Posted on July 09, 2018 at 12:24

Yes, 

Page 33 has a mamory map, with Flash from 08000000 - 0803FFFF.

But my STM32F105RB flash is 128KB, not 256KB. so I want to know this one's flash range.

[AvaTar]

Posted on July 09, 2018 at 13:39

See the reference manual, sect. 3.3.3.

ST's designation scheme (connectivity,low/medium/high density) for the F1 devices is a bit confusing, and had been dropped for later series.

The device might have more Flash physically, which failed product test.

[Tilen MAJERLE]

Posted on July 09, 2018 at 13:40

Datasheet you are referring to is for any STM32F105 in any package and any flash size. Since you have RB = 64-pin package, 128kB flash, you have to look only to first 128kB of flash in memory map.

[Tilen MAJERLE]

Posted on July 10, 2018 at 08:19

Memory map is general for F105 MCU series. As you only have 128kB of flash, take into account only first 128kB of flash in memory map which is in datasheet. Flash starts at address 0x08000000 and is 128kB in size for your MCU.

[Treacy Yao]

Posted on July 10, 2018 at 07:49

Yes, but unfortunately, I can't find the related map of 'only to 128KB flash in memory map'. Could you help me?

[Treacy Yao]

Posted on July 10, 2018 at 08:03

Hello, 

I'm confused. so you mean the STM32F105RBT6(128KB flash, 64KB sram) might have more flash but it can just use 128KB? which means the useful flash range is 

0x08000000-0x0801FFFF, but the physically flash is 08000000 - 0803FFFF. Am I right?

[AvaTar · Accepted solution]

Posted on July 10, 2018 at 08:26

I'm confused. so you mean the STM32F105RBT6(128KB flash, 64KB sram) might have more flash but it can just use 128KB?

This issue had been discussed here some times. It is a matter of economy for ST to sell MCUs as 128kB variants wich have a defect in the second 128kB section. For your question, better ignore that.

 I can't find the related map of 'only to 128KB flash in memory map'.

There is none. Just the mentioned datasheet and reference manual for the F105/F107 parts, which describe the address map for the maximal variant.

MCU variants with less Flash just use only the lower parts/sectors (addresses), and the rest is reserved.

Remember, this series is about 10 years old.