feature-request: It is possible to create a PJON_Receiver to listen on a specific port?

[Cimex97]

Hey,
I want to implement two applications that use the same PJONBus or PJONRouter.
It is possible to set for a port a PJON_Receiver function?
For example:

bus.set_receiver(pjon_receiver_cb, port);

I know that I can use this function:

bus.include(true, port);

But this works only for one port and I won't get other messages.

Some background information:
I have a system with a couple of devices using PJON. This hardware runs with the zephyr-rtos. On the systems runs also the MCUBoot Bootloader that I can upgrade the firmware of the devices remotely. This is done by the SMP(Simple Management Protocol) that comes with the bootloader.

My Idea is to add a port for the SMP and "route" the packets to the zephyr backend, otherwise the application get the packets.

Something like that:

Is this an use case for the PJON protocol?

[gioblu]

Ciao @Cimex97 yes that looks a potential use case for the PJON protocol. Look at the implementation of the setter:
https://github.com/gioblu/PJON/blob/12.1/src/PJON.h#L815

It is made to let you call include_port(true) this sets the port as PJON_BROADCAST then:
https://github.com/gioblu/PJON/blob/12.1/src/PJON.h#L391
because of that, received packets are never dropped whatever is the value of port.

if you set include_port(true) you can then add a couple of conditionals in the receiver function where to choose what to do depending on the port.

void receiver_function(uint8_t *payload, uint16_t length, const PJON_Packet_Info &packet_info) {
  Serial.print("Packet received, ");
  if(packet_info.header & PJON_PORT_BIT) {
    if(packet_info.port == 8001) Serial.print("SMP");
    if(packet_info.port == 9001) Serial.print("APP");
  }
  Serial.println();
}

The only difference is that you need to use one of the send functions specifying which port to use for each packet transmission, for example (from docs):

// All optional parameters available
bus.send_packet(
  10,         // Device id (uint8_t)
  "Hello",    // Payload   (const void *)
  5,          // Length    (uint16_t)
  bus.config, // Header    (uint8_t)  - Use default config
  0,          // Packet id (uint16_t) - Don't include packet id
  8002        // Port      (uint16_t)
);

Let me know if help is required :) it would be cool to see the thing working!

[gioblu]

Ciao @Cimex97 I will document this feature better in v13.0 documentation, thank you for exposing the lack of clarity about this in the documentation.

[Cimex97]

Thank You for the answer. I will try it out and let you know if it works.

[Cimex97]

Hey,
I implement a simple PJONSession class for me to handle this. I can now upgrade my devices, that run with Zephyr-OS, over PJON.
I will create a PR soon for the Zephyr interface.