| 1 | # Linux General/Raspberry Pi |
| 2 | |
| 3 | @tableofcontents |
| 4 | |
| 5 | <!-- markdownlint-disable MD031 --> |
| 6 | RF24 supports a variety of Linux based devices via various drivers. Some boards like RPi can utilize multiple methods |
| 7 | to drive the GPIO and SPI functionality. |
| 8 | |
| 9 | ## Potential PreConfiguration |
| 10 | |
| 11 | If SPI is not already enabled, load it on boot: |
| 12 | |
| 13 | ```shell |
| 14 | sudo raspi-config |
| 15 | ``` |
| 16 | |
| 17 | 1. Update the tool via the menu as required |
| 18 | 2. Select **Advanced** and **enable the SPI kernel module** |
| 19 | 3. Update other software and libraries |
| 20 | ```shell |
| 21 | sudo apt-get update |
| 22 | sudo apt-get upgrade |
| 23 | ``` |
| 24 | |
| 25 | ## Build Options |
| 26 | |
| 27 | The default build on Raspberry Pi utilizes the included **BCM2835** driver from [the BCM2835 Library](http://www.airspayce.com/mikem/bcm2835) |
| 28 | |
| 29 | 1. See [the Linux section for automated installation](linux_install.md). |
| 30 | 2. Manual install: |
| 31 | ```shell |
| 32 | make |
| 33 | sudo make install |
| 34 | ``` |
| 35 | |
| 36 | ## Connections and Pin Configuration |
| 37 | |
| 38 | Using pin 15(GPIO22) for CE, pin 24(GPIO8 commonly labeled as CE0) for CSN |
| 39 | |
| 40 | Can use any available SPI BUS for CSN. |
| 41 | |
| 42 | In general, use |
| 43 | |
| 44 | ```cpp |
| 45 | RF24 radio(<ce_pin>, <a>*10+<b>); |
| 46 | ``` |
| 47 | |
| 48 | for proper constructor to address the correct spi device at /dev/spidev\<a\>.\<b\> |
| 49 | |
| 50 | Choose any GPIO output pin for radio CE pin. |
| 51 | |
| 52 | > [!WARNING] |
| 53 | > The pin numbers may be different for certain systems. |
| 54 | > In this library's examples, we use the BCM pin numbers for BroadCom chips such as |
| 55 | > those used on all Raspberry Pi models. |
| 56 | > |
| 57 | > For Raspberry Pi clones, such as Orange Pi or Banana Pi, defer to the pin numbers described |
| 58 | > in their corresponding documentation/manual. |
| 59 | > |
| 60 | > Hint: If libgpiod is installed (not required for this library), |
| 61 | > then you can use the included |
| 62 | > [CLI tools shipped with libgpiod](https://libgpiod.readthedocs.io/en/latest/gpio_tools.html) |
| 63 | > to gleam system-specific details. |
| 64 | |
| 65 | ### Linux kernel (SPIDEV driver) and the GPIO chip number |
| 66 | |
| 67 | This RF24 library, as of v1.4.9, uses the Linux kernel's Character Device API to interface |
| 68 | with GPIO pins (AKA "lines" in kernel docs). Previous versions used the deprecated "sys fs" interface. |
| 69 | |
| 70 | By default, this library attempts to use pins exposed via `/dev/gpiochip0`. |
| 71 | Some systems have multiple public-facing GPIO chips integrated (ie nVidia Jetson series). |
| 72 | If your system exposes the desired GPIO pins via a different chip (ie `/dev/gpiochip4`), then the |
| 73 | `RF24_LINUX_GPIO_CHIP` can be set to the correct value when compiling the library. |
| 74 | |
| 75 | ```shell |
| 76 | cmake .. -DRF24_LINUX_GPIO_CHIP="/dev/gpiochip4" |
| 77 | ``` |
| 78 | |
| 79 | ### General |
| 80 | |
| 81 | ```cpp |
| 82 | RF24 radio(22, 0); |
| 83 | ``` |
| 84 | |
| 85 | ### MRAA Constructor |
| 86 | |
| 87 | ```cpp |
| 88 | RF24 radio(15, 0); |
| 89 | ``` |
| 90 | |
| 91 | See [the MRAA documentation for Raspberry Pi support](http://iotdk.intel.com/docs/master/mraa/rasppi.html) |
| 92 | |
| 93 | ### SPI_DEV Constructor |
| 94 | |
| 95 | ```cpp |
| 96 | RF24 radio(22, 0); |
| 97 | ``` |
| 98 | |
| 99 | See [the Raspberry Pi documentation about the GPIO pins](https://www.raspberrypi.com/documentation/computers/os.html#gpio-and-the-40-pin-header) |
| 100 | |
| 101 | ### Pins |
| 102 | |
| 103 | | PIN | NRF24L01 | RPI | RPi -P1 Connector | |
| 104 | | --- | -------- | ---------- | ----------------- | |
| 105 | | 1 | GND | rpi-gnd | (25) | |
| 106 | | 2 | VCC | rpi-3v3 | (17) | |
| 107 | | 3 | CE | rpi-gpio22 | (15) | |
| 108 | | 4 | CSN | rpi-gpio8 | (24) | |
| 109 | | 5 | SCK | rpi-sclk | (23) | |
| 110 | | 6 | MOSI | rpi-mosi | (19) | |
| 111 | | 7 | MISO | rpi-miso | (21) | |
| 112 | | 8 | IRQ | - | - | |
| 113 | |
| 114 | ## brief history of RF24 library lineage |
| 115 | |
| 116 | Based on the arduino lib from [J. Coliz](maniacbug@ymail.com), |
| 117 | the library was berryfied by [Purinda Gunasekara](purinda@gmail.com) |
| 118 | then forked from github [stanleyseow/RF24](https://github.com/stanleyseow/RF24) to [jscrane/RF24-rpi](https://github.com/jscrane/RF24-rpi) |
| 119 | |
| 120 | Network lib also based on [farconada/RF24Network](https://github.com/farconada/RF24Network) |