Flash Usage - Block Type

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Flash Usage - Block Type

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wayneyounghoney
Contributor I

I have some questions on the Flash system:

  • Is there any significance or meaning to the Block Type attribute (Low/Mid/High/Large)? Is it some convention indicating where they are located in the memory map, although "High" doesn't seem to be in the high area and "Large" doesn't seem to fit the other terms.
  • Can someone confirm that you can execute code from the lower flash areas (RWW 0,1,2,3,4,5):
    Start addressEnd addressAllocated size (KB)RWW partitionBlock numberBlock typeExample use
    0x000000000x0000FFFF6400LowEEPROM data
    0x000100000x0001FFFF6411LowEEPROM data
    0x000200000x0002FFFF6420MidEEPROM data
    0x000300000x0003FFFF6431MidEEPROM data
    0x000400000x003FFFFF3840Not availablen/a
    0x004000000x00403FFF1600UTESTSee Table 4-3
    0x004040000x005FFFFF2032Not availablen/a
    0x006000000x00603FFF1640HighCSE
    0x006040000x00607FFF1651HighCSE

  • Why do RWWs 0,2 have a Block 0 but RWWs 1, 3 have a Block 1 (and not a Block 0)? Any significance to this?
  • If you do not use the CSE can the RWW 4 and 5 be used for any code or data use?
  • The total available Flash is 8480KB (8192KB of Large and 288KB of Low/Mid/High)
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davidtosenovjan
NXP TechSupport
NXP TechSupport

CSE flash blocks cannot be used for general purpose functionality because of reason below:

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wayneyounghoney
Contributor I

Hi David. Thanks for the info. I appreciate it.

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davidtosenovjan
NXP TechSupport
NXP TechSupport

The block type affects mainly endurance and data retention as you can see below (datasheet screenshot):

pastedImage_1.png

You can execute code from the lower flash areas, but areas with higher endurance (smaller block) are mainly intended for EEPROM emulation, but you can execute code from these area as well. I am not completely sure about CSE blocks, I am finding it out, returning to you.

Regarding blocks and partitions, blocks are numbered in ascending order withing one block type, partitions the same way withing the whole flash. Just matter of implementation.

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wayneyounghoney
Contributor I

The MPC5777C.

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davidtosenovjan
NXP TechSupport
NXP TechSupport

Could you specify used device?

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