nRF51 RAM section size

[Chinook]

Do all revisions of nRF51 have the same 4kB RAM sections with separate RAM AHB slaves? The product specification clearly states that only for revision 3 chips.

[Stefan Birnir Sverrisson]

Hi

The RAM documentation in nRF51822_PS v3.1, section 3.2.2. is specific for third revision and does not apply for second or first revision nRF51

Update 9.7.2015 For nRF51 revision 1 and 2, only one AHB slave is present

[Chinook]

Sure, and that's why I'm asking. So what about the first and second revisions? Do they also have 4KB RAM sections? And are those sections independent AHB slaves? This is important as it allows to avoid conflicts between different AHB masters.

[Chinook]

nRF51 Series Reference Manual Version 2.1 in section 4.1.4 says:

"The RAM is divided into multiple RAM blocks that can be further divided into multiple RAM sections, that is, a RAM block may contain one or more RAM sections. More information about how these RAM blocks are divided can be found in the device specific product specifications."

That means there are at least 2 RAM sections in devices with 16kB RAM. Also block diagram in section 2.1 shows multiple RAM AHB slaves. Is that wrong?

[Stefan Birnir Sverrisson]

Thanks for pointing that out. Made me realize that things don't add up completely. I think I have been wrong about that there was only one RAM section for nRF51 first and second revision. There may be more RAM sections, but they have no real meaning because there is only one AHB slave. It is only for Third revision that there is one AHB slave per 4kB section. This means that the block diagram in nRF51 Reference Manual v2.1, section 2.1, is incorrect, but rather the diagram in nRF51822 PS v2.0, section 2.1 is correct where only one AHB slave is shown for RAM

[Chinook]

Ok, thanks.