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TMS320F28379D: INTOSC2 clock source running at 1.25MHz

Braden Sunwold
Prodigy 150 points

Part Number: TMS320F28379D
Other Parts Discussed in Thread: C2000WARE

Hello,

I am configuring the system clock to 100MHz and the low speed clock to 25MHz. I tried to place in a NOP statement with a GPIO toggle and noticed that the pin toggled WAY slower than I expected (1.6mS). So then I tried to measure the XCLKOUT to verify my clock frequency. I selected INTOSC2 as the XCLKOUT source and can see that it is running with a period of 400nS or 1.25MHz which makes no sense to me? The reference manual states it should be running at 10MHz. I also tried to measure INTOSC1 and also saw the same frequency as the measured INTOSC2. Below is a screen shot of my logic analyzer and register configurations.

I am running off a custom board right now since the LAUNCHPAD dev kit does not breakout the XCLKOUT GPIO. But looking at my NOP test case on the LAUNCHPAD dev kit, I see the same 1.6mS timing so I am assuming this issue is consistent between boards.

Thanks

  • 0
    TI__Guru* 84490 points

    Braden,

    Can you check if the INTOSC1/2TRIM registers have been populated?  These are located in the Analog Sub System register group.  If you see all 0x0000 then the trim has not been loaded.  There should be a call to "Device Cal" function in the examples inside the sys config file to do this.  There may also be a script to do this from the top drop down in CCS.

    If you see a non-zero value then this is not the issue, but I want to start here first. 

    If you could also tell me the values in SYSCLKDIVSEL register that will help as well.

    Best,

    Matthew

  • 0 in reply to MatthewPate
    Prodigy 150 points

    Hi Matthew, 

    Looks like the INTOSC1/2TRIM reg is populated:

    and SYSCLKDIVSEL register field PLLSYSCLKDIV is set to 1.

    Thanks

  • 0 in reply to Braden Sunwold
    TI__Guru* 84490 points

    Braden,

    Can you try one of the  GPIO toggle examples in C2000Ware located here: C:\ti\c2000\C2000Ware_4_01_00_00\driverlib\f2837xd\examples\cpu1\gpio

    Let's see if this gives you what you expect, and then we can work backwards on the delta between this and your code.

    Best,
    Matthew