Running at 1MHz crystal oscillator for RL78/G1D device


This is wearable application, but it doesn’t need much horsepower. So running in low power mode would be fine.  However concern on running with 1 MHz. Here are a few questions regarding the page 15, document  R30UZ0048EJ0100.

1)     Can the 32MHz xtal be replaced with a 1MHz xtal?  Or does the BLE require the higher speed?

2)     When running at 1MHz is BLE operation and communications feasible?

3)     Is the 32KHz crystal required for all timer operation or is it just for the RTC?


Thein Oo

  • Hi,

    Bluetooth stack on the RL78/G1D will NOT be able to run at 1 MHz, but application alone can however run at 1 MHz clock.

    32 KHz crystal is needed for RTC and is not needed for other peripherals.

    Warm Regards


  • In reply to sudhi:

    Hi Sudhi,

    Thanks for your feedback.  So are you saying the 32MHz xtal is required?  Or could it be 24MHz or any other frequency?  


    Larry Chiodi

  • In reply to Larry C.:

    Hi Larry,

    As in Page 13, Section 2.5, BLE Stack needs a 32 MHz clock to function. No discounts on that! :-)

    Warm Regards