RH850 self reprogramming


I want to implement self reprogramming feature in RH850.

For that is it require to connect pull up resistor in FLMD0 pin or can I keep it open ?


My understanding is as follows.For self reprogramming feature implementation,No hardware change is required.

FLMD0 pin can be pulled up by FLMDCNT register. It means software change is enough for self programming implementation.Is it correct ?

  • It's best to have a weak pull-down (at least 100k) on FLMD0. The FLMDCNT register can be used to pull up for programming. Typical internal pull-up resistance for the pin is 19k (max 48k) and the threshold for logic level high is 0.66 x EVCC.

  • Sethu,

    Has your question been answered?

    Mike Clements
    RenesasRulz Moderator
  • In reply to Scott Winder:


    You mentioned 100K pulldown on FLMD0. But if I read RH850/F1L,

    "The FLMD0 pin is made high level by using one of the following methods.

    The FLMD0 pin is externally pulled up.

     The FLMD0 pin is pulled up by the FLMDCNT register.

    The outline of the FLMDCNT register is described in Section"


    So Which one is correct ? Pulldown or pullup at FLMD0 ?

  • In reply to Sethu:

    They're actually both correct. It should be pulled down for normal operation, but for programming it can be either pulled up by an external source (logic level high from a programmer, etc.) or by the internal pull-up resistor (for self-programming). 100k is specified for the pull-down so that it can be easily overcome by the internal pull-up resistance.