I want to time sync my pi using a PPS line from a GPS, but I cannot decipher the pcb schematics well enough to understand how/if the board breaks out the gpio pins of the raspberry pi at all. Is gpio pin 18 specifically broken out somewhere on the Navigator? If not any suggestions on how I can still utilize PPS time syncing?
Hi @bja1701 -
Can you share how you’d like to use the PPS signal within your application? I’ve seen PPS synchronization used for both radio communications and bathymetric survey collection, but would think the time sync that BlueOS performs (when it has internet access or connects to your browser tab) would be “good enough” for most applications?
Generally, you can use the ADC channels for signal inputs, or configure other IO for input . I’d imagine a lua script working with the autopilot may be able to accomplish your goals, depending on what they are…
we are doing research for BYU underwater robotics lab developing AUV’s. We are utilizing Seatrac Modems to communicate between robots underwater. We need the time sync to make the message timing as accurate as possible for some algorithms we are creating. I’m guessing from your answer that there is no direct access to the gpio pins of the pi via the navigator board? If not could you give me more details on using the the ADC or other IO pins with lua? I have never worked with that language before, is that what the navigator board uses?
Hi,
we have only two “spare” gpios. those are the pwm0 on the aux channel and the leak detector input pin. If you do need realtime-ish performance, you should be able to access them directly by using C code in a standard rpi way.
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