Can I use x8 parallelism size for Flash programming with voltage 3.3V?

[Petr1]

According to the user manual for STM32F767 and table "Program/erase parallelism" I should use x32 PSIZE while on 3.3V. But when I want to do programming with single byte access (e.g. bacause of alignment...) is it possible to use lower parallelism modes? From the manual it's not clear to me whether the Parallelism Size setting is considered as "Maximum parallelism" or it's taken as "Required parallelism". If the later is correct then a possible solution for single byte access would be to use 4B access with masking (which slows things down a bit in certain situations).

[waclawek.jan]

> From the manual it's not clear to me whether the Parallelism Size setting is considered as

> "Maximum parallelism"

You mean the Program/erase parallelism table, I presume.

Yes, it is; and yes, it's not clear. The same in other families RM (I checked RM0090).

For assurance, look into the datasheet, Programming voltage in the Flash memory programming tables.

JW

[Petr1]

> For assurance, look into the datasheet, Programming voltage in the Flash memory programming tables.

Thanks for mentioning the datasheet. For my MCU it should be "DocID029041 Rev 6". However it brings even more confusion by stating that for 32b program operation the voltage Vprog should be 3V maximum. Is the Vprog equal to the main voltage line? If so the table seems to be misleading.

Table 58. Flash memory programming:

32-bit program operation 2.7 - 3 V

16-bit program operation 2.1 - 3.6 V

8-bit program operation 1.7 - 3.6 V

Let's suppose it answers my previous question that I can use lower PSIZE modes with higher voltages (though I must say I don't feel 100% sure just by relating to that table above).

They should be more clear about this, shouldn't they...

[waclawek.jan]

Sorry, I did not look into the particular DS (I don't use 'F7).

> They should be more clear about this, shouldn't they...

As much confusing while obviously incorrect these tables are, I wish this to be the least clear issue in the STM32 documentation. There is too much handwaving and too little rigor in them.

JW

[Amel NASRI]

Hi @Petr​ ,

There is an error in datasheet that was already reported in https://community.st.com/s/feed/0D50X00009XkaQqSAJ.

So, for 32b, the maximum Vprog is 3.6V, not 3V.

Based on the table "Program/erase parallelism" of the reference manual, we speak about the maximum parallelism depending on the selected voltage range.

I hope it is clear now.

-Amel