STM32F4xx : 2.5V programming voltage VS. #bits Write/erase flash

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  • STM32F4xx : 2.5V programming voltage VS. #bits Write/erase flash

    Hi,

    I'm developing an electronic board that embeds an STM32F437
    MCU and is programmed via JTAG by J_LINK programmer. The board is
    supplied by 2.5V come from a linear regulator of which the input is
    sourced by a Li-Polymer batterie.
    So, in the STM32F4xx's datasheet,
    the numbers of the bits of flash programming is limitted according to
    the power supply voltage :
    - 2.7V-3.6V => 32 bits
    - 2.1V-3.6V => 16 bits
    - 1.8V-3.6V => 8 bits
    Then, for my application, this will be 16 bits.

    In addition, I use IAR AWARM. Thus, my questions are :

    - Is is possible to program the MCU's system memory with this voltage
    level ? I know that the J_LINK JTAG connector have Vref pin, so, I
    thought that the instruction code data will automatically transfer by
    the J_LINK to the MCU flash memory with the suitable bit number but I
    was probably wrong.

    - So, which configuration can I do in IAR in order that the MCU will be correctly programmed ?

    Thus, I need these information before I make the PCB board to not be wrong about my system power supply level.

    Thanks in advance.

    Best Regards,
    bayarn
  • Hi bayarn,

    One question: What does VTref report when connecting via J-Link Commander?
    Is it 2.5V or 3.3V?


    Best regards
    Alex
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
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  • Hi Bayarn,

    Then it is no problem since the J-Link flashloader already checks against VTref and behaves accordingly.

    Beware: When using IAR make sure that you either use the J-Link flashloader or make sure that the IAR flashloader behaves correctly.
    I am not sure if it considers the MCU voltage.
    For more information about how to configure EWARM to use the J-Link flashloader for flash download in EWARM, please refer to UM08001,
    chapter "Flash download" -> "Setup for various debuggers (internal flash)"

    Download-Link: segger.com/cms/admin/uploads/p…Docs/UM08001_JLinkARM.pdf


    Best regards
    Alex
    Please read the forum rules before posting.

    Keep in mind, this is *not* a support forum.
    Our engineers will try to answer your questions between their projects if possible but this can be delayed by longer periods of time.
    Should you be entitled to support you can contact us via our support system: segger.com/ticket/

    Or you can contact us via e-mail.