Oscilloscope HDQ protocol trigger

We have shared with you the decoding of the HDQ protocol. Today we will take a closer look at the triggering function of this protocol.

　　In the decoding environment, as long as the protocol trigger is set to ON and the [Trigger] key is pressed, the trigger type will automatically change to the decoded HDQ protocol. To turn on the trigger function, you need to set the trigger mode. You can press the trigger mode soft key to automatically change to normal, or you can press the [Auto/Normal] key in the trigger control area on the front panel of the oscilloscope. Next, set the protocol trigger parameters. On the premise of turning on the protocol trigger in the decoding module, you can set it in the protocol parameters in the trigger module or select it in the trigger settings in the protocol parameters in the decoding module.

　　Figure 1 HDQ protocol trigger

　　The trigger module of the HDQ protocol includes two types: reset segment and instruction. We select instruction trigger, set the operation to read register operation, and set the register address to 0x7F. We can see that the protocol waveform on the screen has been accurately triggered. Short press the horizontal offset knob to position the trigger point in the center of the screen. Adjust the hour base, zoom in on the waveform, and observe the correspondence between the protocol and the decoding event. The premise of effective decoding is to detect a complete frame of information. Press the [Horiz] key and set the storage depth to 112Mpts. Setting a large storage depth is more helpful to observe the trigger position of the protocol in detail.