CPU frequency error


There was  power fluctuation when we were flashing the production board which has RH850 controller.  

We tried flashing the board again and from then on, we are getting the following error.

Is there a way to recover from this error?  Can you please helo?

Thanks and regards,

Subasree Venkatesan

  • Dear Subasree Venkatesan,

    the screen shot show that you are using a RH850/P1x-C. It seems that a "Chip erase" was executed which erases also the default Option Byte settings.(A block erase over all block would NOT erase the Option Bytes.). After such a "Chip erase, it is necessary to set the Option Bytes immediately to valid values. If there is a power fluctuation or any other reset during this flow, the Option Bytes may enter an invalid setting.

    This is a disadvntage of RH850/P1x.C serie: Invalid Option Bytes (all 0xffffffff) are a setting, which set the internal clock to a configuration, which is invalid and fail. So, the device try to start with an invalid clock setting and fail. This is not recoverable. The device should be de-soldered and replaced by a new one with valid Option Byte settings (e.g. default values).

    Even Renesas has no chance to recover these Option Bytes by usual tools like Programmer or Debugger, as the device is now incapable to start with a valid clock setting.

    Best regards

  • Hi Thorsten Kreye,

    Thank you.  Does Renesas have any other "unusual tools" to recover these option bytes?  We understand the incorrect option byte 1 has corrupted the clock setting.  But it is important we recover this board without de-soldering the MCU. 

    Kindly help.

    Thanks and regards,

    Subasree Venkatesan

Reply Children
  • Hello Subasree Venkatesan,

    this"unusual tool" is only our production tester in our production line. So, this is even no tool anyone could use, while the device left our production line and is soldered to a PCB. Only in this test mode, while the device is tested, trimmed and configured for delivery, the Option Bytes can be set correctly from erased flash state to default settings. Sorry for this bad news. (Other RH850 devices, except P1x-C do not have this disadvantage (0xffffffff is a valid setting).)

    Best regards