Switch Between Operation Modes

You can use the C0_microSD_toolkit.py script from the Signaloid-Compute-Module-Utilities repository to switch between modes of operation.

The on-board LEDs indicate the active mode:

LED behavior	Meaning
Red solid	Bootloader mode
Green solid	Signaloid SoC mode, application running
Green blinking rapidly	Flash operation in progress; do not remove power
Red or green blinking	SWITCHING state: the blinking LED shows the next boot mode; power-cycle to apply
No LED activity, no host connected	Custom user bitstream loaded; LED behavior is defined by the bitstream

1. Insert the C0-microSD into your computer.

2. Identify the C0-microSD device path. For this example, we assume the device path is /dev/disk4. You can find more details on how to identify your C0-microSD in Identify your module.

3. Verify the active mode.

   • A solid red LED means that the C0-microSD is in Bootloader mode (Figure 1).
   • A solid green LED means that the C0-microSD is in Signaloid SoC mode (Figure 2).

   Figure 1: C0-microSD is in Bootloader mode.	Figure 2: C0-microSD is in Signaloid SoC mode.

4. Run sudo python3 ./C0_microSD_toolkit.py -t /dev/disk4 -s to switch operation mode. If this is successful, the opposite LED of the one that is solid should start blinking (Figures 3 and 4).

   Figure 3: C0-microSD in Bootloader mode switching to Signaloid SoC mode.	Figure 4: C0-microSD in Signaloid SoC mode switching to Bootloader mode.

   Following is an example output of switching the operation mode of a C0-microSD from Signaloid SoC mode to Bootloader mode:

   % sudo python3 C0_microSD_toolkit.py -t /dev/disk4 -s
   
   Signaloid C0-microSD | Loaded configuration: Signaloid SoC | Version: 1.0 | State IDLE
   Switching device boot mode from Signaloid SoC to Bootloader...
   Device configured successfully. Power cycle the device to boot in new mode.
   Done.

5. Power-cycle the C0-microSD to load new configuration mode. This means that the LED that was previously flashing should now be constantly on (Figures 5 and 6).

   Figure 5: Power cycling the C0-microSD to switch to Signaloid SoC mode.	Figure 6: Power cycling the C0-microSD to switch to Bootloader mode.

note

In the visualizations above, the C0-microSD has been inserted into a common off-the-shelf microSD to SD adapter.

Next steps

• Modes and Custom Bitstream, what each mode does and how the bootloader selects between them.
• Flash the C0-microSD, writing an application binary or a bitstream once the module is in Bootloader mode.
• Identify your module, confirming the device path and the active mode.
• Stuck? See Troubleshooting and FAQ.