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TMS320F2811: I want to ask about boot mode.

Juyeol Jung
Prodigy 120 points

Part Number: TMS320F2811

Hello,

GPIO14 is connected with the pull up switch. But this pin is related with the boot mode.

I want to fix the boot mode and use Input port, NOT change the circuit. Please tell me what should I do?

I read the SPRU095C reference document and refer to the codes, but I don't know how to use it.

  • 0
    Guru 192875 points
    Hi,

    What boot mode do you intend to operate in? Flash?

    Regards,
    Gautam
  • 0 in reply to Gautam Iyer
    Prodigy 120 points
    Hi, Gautam
    Thank you for your response.

    The current symptoms are as follows.
    I want to control the rotary switch by using four GPIOs included GPIOF4(related with boot mode) and GPIOF14(related with PLL).
    It consists of pull-up circuits.
    When GPIOF4 is set to 0 and the power is turned on, It is set to other boot mode(Not flash) and system does not work.
    Similarly GPIOF14 is set to 0 and the power is turned on, the system seems to be very slow. (I think the system clock is modified and affected PLL.)
    My .cmd file is already been modified, and start branch address was set to 0x3F 7FF6.

    I would like to force the boot mode to flash and I also want to operate the CPU clock normally. And I want to use four pins only for input GPIOs.
    Is there any solutions without change the circuits?


    Regards,
    Juyeol Jung
  • 0 in reply to Juyeol Jung
    TI__Guru* 95315 points
    Can you post the schematics of the 4 GPIO pins you use for the rotary switch?
  • 0 in reply to Hareesh Janakiraman
    Prodigy 120 points

    Hi, Hareesh

    Thank you for your response.

    My circuit is here.

  • 0 in reply to Juyeol Jung
    TI__Guru* 95315 points

    Upon power-up, the GPIO pins come up as inputs. During this time, the boot-mode pins and the -XPLLDIS pin must be sensed correctly at their desired states for the device to operate properly. In your case, you want both F4 & F14 to be sensed high, so that code-control branches to flash and the PLL is not bypassed. VIH(min) is 2v, per datasheet. So, these 2 pins must be maintained at least at 2v during power-up. From the schematics, it appears your design uses these 4 pins as inputs. You have not provide any details about SW2. I presume this is holding GPIOF4 & GPIOF14 low during power-up. Can you provide a oscilloscope capture of these pins, along with 1.8v & 3.3v during power-up? If F4 & F14 are indeed held low, during power-up, then what you see is as per design spec of the chip. You need to modify your design to ensure these two pins are sensed high.

     

  • 0 in reply to Hareesh Janakiraman
    Prodigy 120 points

    Hi, Hareesh.

    As a result of checking through the oscilloscope, these pins are under 2 voltages and sensed low during power-up.

    It seems like it won't be able to avoid modifying the circuits.

    I really appreciate your help.