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TMS320C6745: Jtag emulation with SPI Boot0 selected

Part Number: TMS320C6745
Other Parts Discussed in Thread: OMAP-L137

We need to clarify a question about boot mode.

Our schematic design configures Boot Mode pins in "SPI0 Flash" mode.

For emulation purpose (JTAG with XDS200)  is it necessary to provide alternative boot mode configurazione as in the picture? Or the connection with emulator is always available (as it seems to me).

We ask because it is not good to have a strong pull-up/pull-down to provide two alternative boot modes on a very fast SPI port.

On the OMAP-L137 EVM, the emulator can connect in any boot configuration except "SPI0 Flash"; but in "SPI0 Flash"  linux OS on ARM starts and maybe it freeze the DSP chip....

  • Hello,

    Could you please re-post the image? I'm unable to view it. 

    You can connect with your emulator in any of the boot modes as long as the DSP is properly woken up/taken out of reset.

    The guidance on pull-ups/downs is shown below for your reference. The concern is around properly latching the boot mode after reset, and for providing flexibility to switch boot modes. In other words, access to the emulator should still be available regardless of the pull configuration.

    For the boot and configuration pins, if they are both routed out and 3-stated (not driven), it is strongly recommended that an external pullup/pulldown resistor be implemented. Although, internal pullup/pulldown resistors exist on these pins and they may match the desired configuration value, providing external connectivity can help ensure that valid logic levels are latched on these device boot and configuration pins. In addition, applying external pullup/pulldown resistors on the boot and configuration pins adds convenience to the user in debugging and flexibility in switching operating modes.

    See the section of the datasheet titled "Pullup/Pulldown Resistors" for details on how to choose values to oppose the internal pullup/pulldown resistors.

    On OMAP-L137, I suspect Linux OS running on the ARM is indeed the reason for not being able to connect to the DSP core via CCS. 



  • The picture was only this page with "SPI0 Flash" and "emulation debug" highlighted. 

    My dubts regards the existence of the row "Emulation Debug".

    However the fact that the emulator can connect also in "SPI0 Flash" mode, resolved my issue. 

  • Pasting the image is not working... hower it was "Appendix A Boot Mode Selection Table".

  • Understood.

    Yes, you can connect to the emulator in any of the boot modes. In the "Emulation Debug" boot mode, both the ARM and DSP are woken up and put into an idle loop after device power-on. This allows emulators to connect to both the ARM and DSP core immediately after boot, whereas in other boot modes the ARM needs to be woken up by the DSP or GEL file. In general, this boot mode does not need to be used and is provided to put the device in a known state without loading a boot image.