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Renesas Electronics America - Knowledgebase

Error message-Boot Failed-Communication Timeout Error_E8a_E8_E7

Last Updated:10/11/2017


When I start up the E8a(E8/E7) emulator (while connecting to target board) [Boot Failed] [Communication Timeout Error] messages appear, and then [Target missing][Cannot find device driver or connection was cancelled] appear and the connection is never made.


The follow are possible causes of this error.

  1. The pin used to connect E8a(E8/E7) and the MCU is incorrect, or the connection does not fit the recommended circuit.
    In this case, please confirm the correct wire connection according to the E8a(E8/E7) Emulator Additional Document for User's Manual for the target MCU.
    Communication between devices may be inhibited if the wire connection does not follow the requirements of the recommended circuit.

    Potential problems: serial resistance applied to the communication signal, no pull-up resistance (wave width is too weak), connection to capacitor, etc.

  2. Faulty MCU
    If the MCU is malfunctioning, the E8a(E8/E7) emulator will also not operate normally.
    This could be caused by one of the following: (note that pin availability differs according to MCU)
    1. Common to all MCUs
      • The MCU input clock is not within specifications or the crystal oscillator is not oscillating correctly.
      • The MCU operating voltage is not within specifications. (Note: operating conditions may differ between mask ROM version and Flash ROM version MCUs.)
      • Even though the MCU is mounted using the IC socket, the connection is faulty (the connection is not through the recommended socket or the screws are not tightened enough, etc.)
      • The MCU has an external watchdog timer that resets the MCU during a break and prevents the emulator from operating normally. Make sure the external watchdog timer is stopped while debugging.
      • Not all of the Vss (GND) pins on the 14-pin connector are connected to the E8a(E8/E7) emulator.
        If some of the Vss (GND) pins are not connected to the E8a(E8/E7) ground, the ground level may remain unstable and cause the MCU to malfunction. All Vss (GND) pins of the E8a(E8/E7) emulator's 14-pin connector must be connected to ground to ensure normal operations.

    2. H8 Family
      • Incorrect handling of the TEST pin
      • Incorrect handling of stabilizing pins such as the VCL pin.
      • When connecting the E8a(E8/E7) emulator to H8/38104F or H8/38124F, external clock input is required for operations but not being input for some reason (when using on-chip oscillator).
      • MCU has current leakage and power-on reset cannot be performed
        1. Check for specific leaks from any of the pins on the MCU to the VCC.
        2. Even if power supply to the user system (MCU) drops, if voltage is supplied to the I/O port pins or analog input pins , current will leak to the VCC pin or AVCC pin from the MCU internal circuit. Not only will this disable the power-on reset for the MCU, it is in violation of the MCU specifications.
        3. Make sure voltage is not supplied to the I/O port pins or analog input pins when the user system (MCU) is turned off.

    3. M16C Family (including R8C Family)
      • If the target MCU has an NMI pin, the NMI pin may be set to L or left open. If so, unintentional NMI interrupt may occur and the emulator will not operate normally. Make sure the NMI pin is pulled up.
      • When operating in the memory extension mode, the RDY or HOLD pin is fixed so that wait or hold is enabled.

  3. Other causes
    1. Common
      • The device selected in the E8a (E8/E7) emulator and the actual target MCU do not match.
      • The ACT lamp of the E8a (E8/E7) was turned off, even if the USB cable is connected.

      For E8a user
      In this case, the E8a is faulty or the USB cable may not be connected completely.

      For E8/E7 user
      Please shut down the High-performance Embedded Workshop first, and make sure that the DIP switch of the E8/E7 is set to "1". After removing the USB connecter from the host PC, insert it again. Then, restart HEW please.

    2. H8 Family
      • Power-on timing differs according to target board When supplying external power to the board, make sure you turn the power on after the following message appears: [Power on target board and press <Enter> key.] The MCU embeds a circuit for communication with E8a(E8/E7) that is initialized only during power-on reset. (as well as when emulator is re-connected)
      • The incorrect frequency is input in the System Clock input dialog.
        Make sure the frequency for the external input clock is entered even for MCUs that divide frequency by 2 internally, such as the H8/300L SLP Series.

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