【ESP32-C2 Contiki移植到LoRa的步骤详解】-优快云博客

ESP32-C2 Contiki移植到LoRa LLCC68的步骤

环境准备
确保已安装ESP-IDF开发环境，并配置好Contiki-NG源码。下载LLCC68的驱动库，通常厂商会提供SPI接口的驱动代码。

硬件连接
将LLCC68模块与ESP32-C2通过SPI连接，典型接线如下：

SCK -> GPIO18
MOSI -> GPIO23
MISO -> GPIO19
CS -> GPIO5
RST -> GPIO4
DIO0 -> GPIO2

Contiki-NG网络栈配置
修改project-conf.h文件，启用LoRa物理层：

#define NETSTACK_CONF_RADIO llcc68_driver
#define LORA_CONF_ENABLED 1

驱动层实现
创建llcc68-driver.c文件，实现Contiki的radio接口：

#include "contiki.h"
#include "net/netstack.h"
#include "dev/radio.h"
#include "llcc68.h" // 厂商提供的驱动头文件

static int init(void) {
    llcc68_init();
    return 0;
}

static int prepare(const void *payload, unsigned short payload_len) {
    llcc68_set_payload_length(payload_len);
    return 0;
}

static int transmit(unsigned short transmit_len) {
    return llcc68_transmit();
}

static int send(const void *payload, unsigned short payload_len) {
    prepare(payload, payload_len);
    return transmit(payload_len);
}

static int read(void *buf, unsigned short buf_len) {
    return llcc68_receive(buf, buf_len);
}

const struct radio_driver llcc68_driver = {
    init,
    prepare,
    transmit,
    send,
    read,
    // 其他必要函数指针
};

SPI接口初始化
在main.c中初始化硬件SPI：

void app_main() {
    spi_bus_config_t buscfg = {
        .miso_io_num = GPIO_NUM_19,
        .mosi_io_num = GPIO_NUM_23,
        .sclk_io_num = GPIO_NUM_18,
        .quadwp_io_num = -1,
        .quadhd_io_num = -1
    };
    spi_bus_initialize(SPI2_HOST, &buscfg, SPI_DMA_CH_AUTO);
    
    llcc68_init_spi(GPIO_NUM_5); // CS引脚
    NETSTACK_RADIO.init();
}

Python测试代码实现

硬件要求
需要另一台LoRa设备或网关作为接收端，如SX1276模块。

测试脚本

import serial
import struct
import time

ser = serial.Serial('/dev/ttyUSB0', 115200)  # 根据实际端口修改

def send_test_packet():
    preamble = bytes([0xAA]*4)
    header = struct.pack('!BB', 0x01, 0x0A)  # 类型和长度
    payload = b'Contiki_test'
    checksum = sum(payload) & 0xFF
    packet = preamble + header + payload + bytes([checksum])
    
    ser.write(packet)
    print(f"Sent: {packet.hex()}")

def receive_loop():
    while True:
        if ser.in_waiting:
            data = ser.read(ser.in_waiting)
            print(f"Received: {data.hex()}")
        time.sleep(0.1)

if __name__ == '__main__':
    send_test_packet()
    receive_loop()

验证步骤

在ESP32-C2上运行Contiki-NG的RIME广播示例
使用逻辑分析仪确认SPI通信波形
通过Python脚本发送测试数据包，检查ESP32的串口日志输出
使用Wireshark抓取LoRa MAC层数据包

关键函数实现细节

LLCC68初始化函数

void llcc68_init() {
    // 复位脉冲
    gpio_set_direction(RST_PIN, GPIO_MODE_OUTPUT);
    gpio_set_level(RST_PIN, 0);
    ets_delay_us(100);
    gpio_set_level(RST_PIN, 1);
    ets_delay_us(5000);
    
    // 检查器件ID
    uint8_t id = llcc68_read_reg(REG_VERSION);
    assert(id == 0x12); // LLCC68的预期ID值
    
    // 配置LoRa模式
    llcc68_write_reg(REG_OP_MODE, MODE_LORA | MODE_STDBY);
    llcc68_write_reg(REG_FREQ_MSB, 0xD9); // 868MHz频段
    llcc68_write_reg(REG_FREQ_MID, 0x06);
    llcc68_write_reg(REG_FREQ_LSB, 0x66);
    llcc68_write_reg(REG_PA_CONFIG, 0xFF); // 最大功率
}

数据收发函数

int llcc68_transmit() {
    llcc68_write_reg(REG_OP_MODE, MODE_LORA | MODE_TX);
    while(!(llcc68_read_reg(REG_IRQ_FLAGS) & IRQ_TX_DONE));
    llcc68_write_reg(REG_IRQ_FLAGS, IRQ_TX_DONE);
    return 0;
}

int llcc68_receive(void *buf, uint16_t len) {
    llcc68_write_reg(REG_OP_MODE, MODE_LORA | MODE_RX_CONTINUOUS);
    if(llcc68_read_reg(REG_IRQ_FLAGS) & IRQ_RX_DONE) {
        uint8_t rx_len = llcc68_read_reg(REG_RX_NB_BYTES);
        llcc68_read_fifo(buf, min(rx_len, len));
        llcc68_write_reg(REG_IRQ_FLAGS, IRQ_RX_DONE);
        return rx_len;
    }
    return 0;
}