F28335 Flash Optimization

Jonathan Riger

I'm working with a SYS/BIOS project that runs from flash. To speed up operation I'm a flash optimization routine. Most of the flash register settings work as expected. I run into an issue with PAGEWAIT and ENPIPE.

We are using a clock rate of 144MHz. With this clock rate decreasing the PAGEWAIT below the default or enabling the pipeline causes the code to jump to an unexpected locations. After the jump, all instructions in the disassembly window appear as ITRAP0's.

We are using CCSv5.5.0.00077 with SYS/BIOS version 6.35.4.50.

The following is our flash initialization in the "good" state:

#pragma CODE_SECTION(InitFlash, "SecureRamFuncs")
void InitFlash(void)
{
    EALLOW;

    FlashRegs.FPWR.bit.PWR = 3;
    FlashRegs.FSTATUS.bit.V3STAT = 1;
    FlashRegs.FSTDBYWAIT.bit.STDBYWAIT = 0x01FF;
    FlashRegs.FACTIVEWAIT.bit.ACTIVEWAIT = 0x01FF;
    FlashRegs.FBANKWAIT.bit.RANDWAIT = 5;
    FlashRegs.FBANKWAIT.bit.PAGEWAIT = 15;   // If this is less than 15 the code behaves unpredictably.
    FlashRegs.FOTPWAIT.bit.OTPWAIT = 8;
    FlashRegs.FOPT.bit.ENPIPE = 0;   // If this is 1 the code behaves unpredictably.

    EDIS;

    NOP10;
}    // End void InitFlash(void)

SecureRamFuncs are loaded into L03SARAM. A memcpy is used to transfer the code from flash into RAM. The registers are changing as expected.

Thank you for your help.

over 11 years ago

0 David M. Alter over 11 years ago

TI__Guru 61235 points

Jonathan,

That is very strange. Are you running on a TI dev board, or is it your own board?

If a dev board, try the non-bios flash example in appnote SPRA958.

http://www.ti.com/mcu/docs/litabsmultiplefilelist.tsp?sectionId=96&tabId=1502&literatureNumber=spra958l&docCategoryId=1&familyId=1414

If your own board, you can still run the example but you probably will want to modify file gpio.c to shut off the PWM and LED blinking pin in case there is contention on your board. Also, check the PLL configuration in sysctrl.c.

I don't see how SYS/BIOS could have anything to do with this problem.

Have you checked the power supply rails on your board (3.3V and 1.9V)?

Regards,

David

0 Jonathan Riger over 11 years ago in reply to David M. Alter

Prodigy 90 points

Hi David,

Thank you for your response. We are using a custom board and managed to solve the issue. I took your advice of loading the f28335 example flash project into the memory. When that worked I loaded the code into a TI dev board. This helped point out that there was an issue with the external interface. As it turns out the external interface was improperly configured, causing unpredictable results. The uninitialized flash covered up these problems.

Thank you for your help,

Jonathan

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F28335 Flash Optimization