【ESP32-S3与LoRa LLCC68的Contiki低功耗自组网实现-详细】

1. ESP32-S3与LoRa LLCC68的Contiki低功耗自组网实现（一）

硬件初始化配置

ESP32-S3需配置SPI接口与LLCC68通信，确保引脚映射正确。SPI时钟频率建议设置为8MHz，以满足LLCC68的时序要求。LLCC68的复位引脚（NRST）和中断引脚（DIO1）需连接至ESP32-S3的GPIO。

#include "driver/spi_master.h"
#include "driver/gpio.h"

#define LORA_SPI_HOST    SPI2_HOST
#define LORA_MISO_GPIO   GPIO_NUM_12
#define LORA_MOSI_GPIO   GPIO_NUM_11
#define LORA_SCLK_GPIO   GPIO_NUM_10
#define LORA_CS_GPIO     GPIO_NUM_9
#define LORA_RST_GPIO    GPIO_NUM_8
#define LORA_DIO1_GPIO   GPIO_NUM_7

spi_device_handle_t lora_spi;
void spi_init() {
   
   
    spi_bus_config_t buscfg = {
   
   
        .miso_io_num = LORA_MISO_GPIO,
        .mosi_io_num = LORA_MOSI_GPIO,
        .sclk_io_num = LORA_SCLK_GPIO,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1,
        .max_transfer_sz = 4096
    };
    spi_device_interface_config_t devcfg = {
   
   
        .clock_speed_hz = 8 * 1000 * 1000,
        .mode = 0,
        .spics_io_num = LORA_CS_GPIO,
        .queue_size = 7
    };
    spi_bus_initialize(LORA_SPI_HOST, &buscfg, SPI_DMA_CH_AUTO);
    spi_bus_add_device(LORA_SPI_HOST, &devcfg, &lora_spi);
}

Contiki网络协议栈集成

Contiki的RIME协议栈需与LoRa物理层适配。修改rimeaddr结构以支持LoRa的16位短地址，并覆写packetbuf相关函数实现LoRa帧格式封装。

#include "net/rime/rime.h"
#include "net/packetbuf.h"

void lora_packet_send(const void *data, uint16_t len) {
   
   
    uint8_t buffer[256];
    buffer[0] = 0x01; // LoRa帧头（示例）
    memcpy(buffer + 1, data, len);
    LLCC68_Send(buffer, len + 1);
}

void packetbuf_adaptor_init() {
   
   
    packetbuf_set_attr(PACKETBUF_ATTR_RADIO_TXPOWER, 14);
    packetbuf_set_data_callbacks(lora_packet_send, NULL);
}

低功耗调度策略

ESP32-S3需进入Light-sleep模式，通过LLCC68的DIO1中断唤醒。Contiki的etimer需与RTC时钟同步，避免唤醒后时钟漂移。

#include "esp_sleep.h"
#include "contiki.h"

PROCESS(lora_network_process, "LoRa Network Process");
PROCESS_THREAD(lora_network_process, ev, data) {
   
   
    PROCESS_BEGIN();
    while(1) {
   
   
        etimer_set(&timer, CLOCK_SECOND * 10);
        PROCESS_WAIT_EVENT_UNTIL(etimer_expired(&timer));
        gpio_wakeup_enable(LORA_DIO1_GPIO, GPIO_INTR_HIGH_LEVEL);
        esp_light_sleep_start();
    }
    PROCESS_END();
}

自组网路由实现

基于Contiki的uip-ds6-route模块扩展，添加LoRa信号强度（RSSI）作为路由度量。使用Trickle算法控制路由更新频率。

#include "net/ipv6/uip-ds6-route.h"

#define LORA_RSSI_THRESHOLD   -80

void route_update(const uip_ipaddr_t *dest, int16_t rssi) {
   
   </