4.2.9. Advanced configuration

The Advanced settings enable you to change the global configuration settings for the RealView ICE unit. Such settings include debug connection mode settings and reset settings. Before you can configure the advanced settings, you must ensure that the control pane displays the advanced controls. See Figure 4.26.

Figure 4.26. Displaying the advanced controls

Displaying the advanced controls

To configure reset behavior:

  1. Set the Reset Type that the RealView ICE run control unit uses to reset the target hardware:

    nSRST

    Resets the hardware by holding the hardware nSRST system reset signal LOW. This is the default.

    nTRST

    Resets the target TAP by holding the nTRST TAP reset signal LOW.

    nSRST+nTRST

    Resets the hardware and the target TAP by holding both the hardware nSRST system reset signal and the nTRST TAP reset signal LOW.

    Fake

    Resets the system by entering supervisor mode, and setting the program counter to the address of the reset vector (known as a soft reset).

    Ctrl_Reg

    The Control register. This reset, in instances where cores have a reset register, enables you to reset the core without using the external reset lines. If you set the reset type to Ctrl_Reg, then this control register is used. See Control register reset.

    For nTRST and nSRST target hardware pull-up resistor values, see RealView ICE reset signals.

  2. Set the required default reset behavior:

    • Select Perform TAP reset on first connect to reset the target hardware whenever you connect.

    • Select Reset On Disconnect to reset the target hardware whenever you disconnect.

  3. Enter appropriate values in milliseconds for the reset hold times and delays:

    • nSRST Hold Time (ms) specifies how long the RealView ICE run control unit holds the hardware nSRST system reset signal LOW

    • nSRST Post Reset Delay (ms) specifies how long after the hardware nSRST system reset before the RealView ICE run control unit enters the Post Reset State

    • nTRST Hold Time (ms) specifies how long the RealView ICE run control unit holds the nTRST TAP reset signal LOW

    • nTRST Post Reset Delay (ms) specifies how long after the nTRST TAP reset before the RealView ICE run control unit enters the Post Reset State.

  4. Select TAP Reset via State Transitions if you want the JTAG logic in the target hardware to be reset by forcing transitions within its state machine. This is done in addition to holding the nTRST TAP reset signal LOW. Select this option if nTRST is not connected, or if the target hardware requires that you force a reset of the JTAG logic whenever resetting.

  5. Select Target nSRST + nTRST linked if the target hardware has its nSRST and nTRST JTAG signals linked.

  6. Allow ICE to perform TAP reset. Set this item to True to allow RVI to hold the nSRST line active long enough to perform any post-reset setup that might be required after a target-initiated reset. This can extend the time that the target is held in reset. If this item is set to False, RVI does not assert the reset line, but post-reset setup might not be complete before the target starts to run.

  7. Allow ICE to latch System Reset. Set this item to True to allow RVI to perform nTRST reset while holding nSRST. This ensures that the TAP state machine and associated debug logic is properly reset.

  8. nTRST High and nSRST High modes. Selects the drive strength used when the reset signal is in the high, or inactive, state. Output can be driven as a strong or weak high, or not driven (tri-state).

  9. nTRST Low and nSRST Low modes. Selects the drive strength used when the reset signal is in the low, or active, state. Output can be driven as a strong or weak low, or not driven (tri-state).

  10. LVDS Debug Interface mode. This can be set either to JTAG or SWD. If set to SWD, this causes RVI to connect to the target using the SWD protocol instead of JTAG. For more information on SWD, see Appendix F Serial Wire Debug. See also Appendix E Hardware Variants for details on determining the hardware that you’re using.

  11. Use SWJ Switching. If this is set, it causes the SWJ switching sequence to be sent before connecting to the core. On cores that support SWJ switching, this causes the core to switch its interface to the selected protocol.

  12. Use deprecated SWJ Sequence. If this is set, it causes RVI to use an alternative SWJ switching sequence, used on some older SWD-compatible targets. This option is normally clear, unless the core requires the deprecated sequence.

    Note

    The LVDS Debug Interface mode, Use SWJ Switching, and Use deprecated SWJ Sequence controls are not present in the control pane if you are not using an LVDS probe.

  13. Set the SWO Mode to Manchester or UART, depending on the mode used by the target.

  14. If the SWO Mode is set to UART, you must set the SWO UART Baud rate for the frequency of the incoming data. If you set this to 0, the system attempts to autodetect the baud rate.

    Note

    UART mode in the SWO context also means Non Return to Zero (NRZ) mode.

Note

These settings are sent to a RealView ICE run control unit whenever you connect to the unit from RealView Debugger. They are used as the default reset behavior for all target hardware that you debug with that run control unit. You can override these settings when you are debugging, as described in Using the Debug tab of the RealView Debugger Register pane.

Recommended settings for an ARM Emulator board

If you are using an ARM Emulator™ board, ARM Limited recommends that you use the default settings. These are shown in Figure 4.27.

Figure 4.27. Recommended settings for an ARM Emulator board

Recommended settings for an ARM Emulator board

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