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CC2640R2F: Does a flash erase result in a reset of the FCFG?

LllL
Prodigy 30 points

Part Number: CC2640R2F

There seem to be multiple variants of the CC2640R2F with regards to the writability and/or erasability of the CCFG and FCFG settings (Section 7.5.2 from the Technical Reference Manual).
However, there seems to be little documentation on how the FCFG can be used exactly.

My main question is how do I know what type of CC2640R2F chip I have? Is there any register I can read to figure out if the FCFG on this particular device is locked?
Is there any way of knowing if a flash erase will result in an erase of the FCFG?

  • 0
    TI__Guru 58425 points

    Hi Lenw,

    There is only one "default" version of the chip, the others of the table are special case only. A normal device is "Customer development" where the other "customer cases" list ways to lock the device down further. Note the "(4)" on most additional settings here as they are a CCFG level protection flag which means it holds from a SW point of view but could be mass-erased using the JTAG chip erase function (unless JTAG is also disabled).

    In general, assume that FCFG is fixed and that you can not erase or write this region (or any TI locked section). The CCFG could be erased as it is part of the "normal" FLASH range. Depending on the CCFG settings you flash to the device, certain FLASH pages might be write/erase protected (from a SW point of view). 

  • 0 in reply to IUsedToBeARealPerson (M-W)
    Prodigy 30 points

    Hi M-W,

    Thank you for the clarification, I do have a few additional questions.

    Is there any visual difference between a "Customer development" chip and a "Packed die"?
    Can a "packed die" be ordered? And if so, what would be the part number? 

    M-W said:
    Note the "(4)" on most additional settings here as they are a CCFG level protection flag which means it holds from a SW point of view but could be mass-erased using the JTAG chip erase function (unless JTAG is also disabled).


    From what I can tell you can always do a mass erase through JTAG, even if JTAG is disabled in the CCFG? 

    M-W said:
    In general, assume that FCFG is fixed and that you can not erase or write this region (or any TI locked section). The CCFG could be erased as it is part of the "normal" FLASH range. Depending on the CCFG settings you flash to the device, certain FLASH pages might be write/erase protected (from a SW point of view). 


    This brings up another question, from the documentation it seems like the CCFG is stored in Flash from address 0x0001FFA8 onwards. Additionally, the CCFG is readable in the range  0x50003FA8 - 0x50003FFF.
    FCFG1 is readable in the range 0x500010A0 - 0x500013BC.

    However, it is not clear to me where this FCFG is stored exactly on the device?
    According to the reference manual the FCFG is "Currently a separate Flash block", but it is not listed in the CC2640RF memory map.
    Additionally, the manual mentions a "Read Only ENGR" 1KB block that is "writeable through FMC", what do the ENGR and FMC abbreviations stand for?

    Furthermore, it seems like JTAG can be disabled on three levels: eFuse, FCFG, CCFG. 
    How would one blow the JTAG eFuse?
    Is the state of that fuse overridden by the FCFG setting (manual states "JTAG TAP/DAP lock override")? 

  • 0 in reply to LllL
    TI__Guru 58425 points

    Hi Lenw,

    No, it cannot. You could argue that this table is not actually of any value for customers. Only one flavor is delivered to market while the table contain potential combinations in the IC development cycle. 

    On the topic of mass erase, there is multiple levels. You can disable the part of the JTAG TAPS which effectively disables debug access but leaving the mass-erase trigger open (the JATG interface is not disabled, it is only a matter of access). You can take that even a step further by disallowing the chip erase to proceed which means you could also not mass-erase.

    On the  memory map section, you can consider the "0x5000xxxx" CCFG and FCFG as being due to address aliasing. Basically, CCFG is located at the end of the user accessible flash and can from software either be read there, or via the alias. The latter simplifies software for devices with different flash sizes. Where FCFG is located is not really important as it is a read only region that can't be altered in any way.

    As for the eFUSE, due to the same reasons a above, there is no way for you to manually blow any additional fuses. What you can control is the CCFG content and the rest is fixed.