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Clock settings

Milton Godinho

Hi!

I am using a STR912FA44 uC and I have a working firmware at 48MHZ and I am trying to increase these freq to 96 MHZ but for some reason the device is not recognize by the PC anymore. I see that the led's blink much faster (according to the increased freq) but the usb communication is gone. This is the code:

previous definitions (working @ 48MHZ)

  SCU_MCLKSourceConfig(SCU_MCLK_OSC);
  SCU_PLLFactorsConfig(192, 25, 3);
  SCU_PLLCmd(ENABLE);
  SCU_MCLKSourceConfig(SCU_MCLK_PLL);

  SCU_AHBPeriphClockConfig(__VIC, ENABLE);
  SCU_AHBPeriphReset(__VIC, DISABLE);
  /*USB clock = MCLK= 48MHz*/
  SCU_USBCLKConfig(SCU_USBCLK_EXT);
  /*Enable USB clock*/
  SCU_AHBPeriphClockConfig(__USB, ENABLE);
  SCU_AHBPeriphReset(__USB, DISABLE);
  SCU_AHBPeriphClockConfig(__USB48M, ENABLE);
  /* Enable and configure the priority of the USB_LP IRQ Channel*/
  VIC_DeInit();

New Code (working @96 MHZ but USB com not working)

  SCU_MCLKSourceConfig(SCU_MCLK_OSC);
  FMI_Config(FMI_READ_WAIT_STATE_2,FMI_WRITE_WAIT_STATE_0, FMI_PWD_ENABLE,FMI_LVD_ENABLE,FMI_FREQ_HIGH);
SCU_PLLFactorsConfig(192, 25, 2);
  SCU_PLLCmd(ENABLE);
  SCU_MCLKSourceConfig(SCU_MCLK_PLL);

  SCU_AHBPeriphClockConfig(__VIC, ENABLE);
  SCU_AHBPeriphReset(__VIC, DISABLE);
  /*USB clock = MCLK= 48MHz*/
  SCU_USBCLKConfig(SCU_USBCLK_EXT);
  /*Enable USB clock*/
  SCU_AHBPeriphClockConfig(__USB, ENABLE);
  SCU_AHBPeriphReset(__USB, DISABLE);
  SCU_AHBPeriphClockConfig(__USB48M, ENABLE);
  /* Enable and configure the priority of the USB_LP IRQ Channel*/
  VIC_DeInit();

Thanks a lot for all your help and wish a great 2009!

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