NRF52DK NRF52832 with LoRa module SX1278

[zazas321]

Hello. I am trying to communicate with LoRa module SX1278 :

The pinout of this module is as following:

I have NRF52DK NRF52832 board:

https://www.nordicsemi.com/Products/Development-hardware/nrf52-dk

Just to get things going, I have found this library that uses SX1276 and I decided to use this as a reference for my project:

https://github.com/craigpeacock/Zephyr_LoRaWAN/tree/main/LoRa

I got a few questions immediately regarding how to properly configure the module:

1. As you can see form the SX1278 LoRa module pinout, apart from the SPI pins, it has DIO0,DIO1,DIO2,DIO3,DIO4,DIO5. Some LoRa libraries I have found utilize only DIO0 while others require all 6. The example project that I provided link to by craigpeacock utilize only 3 DIO's:
   Theres an example of his overlay for the NRF52840:
   

   &spi1 {
   	compatible = "nordic,nrf-spim";
   	status = "okay";
   	cs-gpios = <&gpio1 15 GPIO_ACTIVE_LOW>;
   	pinctrl-0 = <&spi1_default>;
   	pinctrl-1 = <&spi1_sleep>;
   	pinctrl-names = "default", "sleep";
   	lora: sx1276@0 {
   		compatible = "semtech,sx1276";
   		reg = <0>;
   		reset-gpios = <&gpio1 13 GPIO_ACTIVE_LOW>;
   		dio-gpios = <&gpio0 24 (GPIO_PULL_DOWN | GPIO_ACTIVE_HIGH)>,
   					<&gpio0 22 (GPIO_PULL_DOWN | GPIO_ACTIVE_HIGH)>,
   					<&gpio0 17 (GPIO_PULL_DOWN | GPIO_ACTIVE_HIGH)>;
   		power-amplifier-output = "pa-boost";
   		spi-max-frequency = <125000>;
   	};
   };

   
   
   . Can someone help me understand why is that?
   
   
2. sx1278 is not oficially supported by Zephyr:
   
   perhaps someone had some experience with this and knows if it is possible to use sx1276 binding and still achieve successfull communication with the sx1278 device?
   
   
3. One of the required properties of the semtech,sx1276 is the power-amplifier-output:
   
   From what I have seen, most people set this property to 'pa-boost'. I didint manage to find any clues about what `pa-boost` means. Could someone provide some information regarding this?
   
   
4. Can I use any GPIO's from the NRF52DK board for the sx1278 DIO's? Can I use GPIO's that are reserved for example I2C0 or I2C1 or even leds?

[runsiv]

Hi Lukas 

1. From what I can see DIO1-3 is used for SPI, Where DI01 is DCLK, DIO2 is Data and I would guess DIO0 is a kind of SS/CS pin.  From the datasheet of the radio is does not specify what DI03-5 is used for excpet it is software configured. Here is a link to the datasheet for the radio. 

2. I see in the Zephyr documentation a few boards that has SX1276/SX1278 chips, so I would presume it works, since the SX1278 is a SX1278 with reduced bandwith. 

3. PA boost stands for Power amplifier boost and it either enables or disables the power amplifier boost mode of the radio as you can see here

4. You can view the Connector interface at our infocenter There is a few pins with defualt setings that you should take into condiseration. 

Regards

Runar