Programming an Empty RL78 MCU

I am following the procedure in R01AN0815EJ0100 to develop a on board programming an empty RL78 MCU.

 

From the procedure, I can control the Reset and TOOL0 on off timing.  But I seems to be unable to get the MCU to enter into the programming mode.  I would like to find out, if there is other documents related to this procedure.

 

If my hardware is connect using the Two-wire UART connection.  During the power on, I do not send the "1-byte data for setting mode" and the "Baud Rate set command frame"  Will the MCU go into programming mode?

 

Regards,

Al Su

  • Al,

    Let me see if I understand your question:

    1. How do you manually set an RL78 MCU into programming mode?
    2. What, if any, UART commands are necessary.

    Is this correct?

    Mike Clements
    RenesasRulz Moderator
  • Al,

    If you do not send the "1-byte data for setting mode", the MCU will NOT go into programming mode. However, you can use Hardware timing instead of a UART on Tool0.

    Between timing points <5> and <6>, the Tool0 line must go to logic low for 78.125uSEC, which is the same timing as "00h" @ 115,200 bps. You can use an external MCU to create 78.125uSEC logic low pulse.

    -MikeC.

  • Al,

    Did Mike's answer solve your issue?

    Mike Clements
    RenesasRulz Moderator
  • This thread will be archived due to inactivity.

    Mike Clements
    RenesasRulz Moderator
  • In reply to Mike Clements:

    same issue i am facing . Can you send a sample code regarding single wire uart
  • At the end it was still timing issue. On my platform, I am using Arm A9 under embedded Linux environment. So from User Space layer, the timing is not as accurate as using a MCU to control. Thus I have to create a loop and adjusting the timing between RESET HIGH and the UART command 00h on Tool0. Also when pulling RESET pin HIGH, there is about 4~5 msec charging time. So if 00h is issued too soon, it may miss the timing windows. So this is the timing that I adjusted in the loop. I also reduced the baudrate of 00h down to slowest 150bps instead. Hope this is helpful to you.