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TMS320F2812 flashburn problem

Xin Lei Zhang
Prodigy 40 points
Other Parts Discussed in Thread: TMS320F2812

  Hello! I'm a new DSP user and I'm trying to burn a serial port communication program into the flash of TMS320F2812 with CCS v3.3. From the datasheet, I have read that the GPIOF4 (SCITXDA) pin shoud connect with 3.3V before the flashburn. Now I have two questions:

  1. After the program is burned into the flash, when the emulator is disconnected, the 2812 chip will be boot from flash. At that time, the GPIOF4 (SCITXDA) pin should still connect with 3.3V or not? If the pin should still connect with 3.3V,  is there any influence about the transfer data of the serial port?

  2. I want to add a hardware breakpoint before the into the program but failed. Should I add the breakpoint after the flashburn, or just before that? Besides, how could I add the hardware breakpoint successfully?

  Thanks for your help!

  • 0
    Expert 1315 points

    Hi Xin Lei Zhang,

    Are you referring to GPIOF4 as a Boot Mode Selection pin? I do not believe anything special has to be done with that pin during flash programming (is this what you mean by flashburn?). However, once the flash is programmed, in order to make the device jump to your code in flash, the boot pins have to be in the correct state. In fact, the 'Jump to Flash' boot mode is the default, so you don't actually have to do anything to the boot mode pins to make this happen: GPIOF4 has to be high, but it is pulled up in the device and if it is high, the state of the other boot mode pins is irrelevant. So just make sure there is nothing pulling that pin low during device power up and you should be OK. To be sure, it would not hurt to add a stronger pull up to the pin (10k ?) and that should not interfere with operation of the SCI peripheral.

    You also have to ensure that you program a branch instruction to address 0x3F7FF6 (also in flash) that jumps to the start location of your code.

    Hope this helps.

    Cheers,

    John.

  • 0 in reply to John Wilkes
    Prodigy 40 points

    Dear John:

       Thanks for your help.

       I want to make sure the what I should do during flash programming.

       You mean once the flash is programmed, I shoud keep the Boot Mode Pin GPIOF4(SCITXDA)  high all the time and do not concern with other boot mode pins during device power up, and the states of GPIOF4(SCITXDA) pin should not interfere with operation of the SCI peripheral, is that right?

       But should I add a resisitor (10k?) between the GPIOF4(SCITXDA) pin and 3.3V during flash programming?

       Thank you.

       Xin Lei Zhang

  • 0 in reply to Xin Lei Zhang
    Expert 1315 points

    Hi Xin Lei Zhang,

    During flash programming you are not required to do anything with the GPIOF4 pin (or any other GPIO pin for that matter).

    During boot, after the flash has been programmed, you must ensure that GPIOF4 is high. You can do this by leaving it unconnected. Since your application is to do with serial port communication, I assume that you will want to use this pin as the SCI_TX output. If this is connected to something that tends to pull the pin down, then an additional pull up resistor (10k or maybe less) will be required to keep the pin high during boot.

    Does this make sense?

    Cheers,

    John.

  • 0 in reply to John Wilkes
    Prodigy 40 points

    Dear John:

       Thanks for your help.

        Your answer helps me a lot and I think I got the key. 

        I will try as your said.

       Thank you.