目录
一、前言
二、主函数逻辑
三、lgw_start函数
四、lgw_connect函数
五、lgw_soft_reset函数
一、前言
对于lora_pkt_fwd.c主函数实现功能的流程不熟悉的话，可以看上一篇文章。本篇文章就集中器开始进行整理。
二、主函数逻辑
i = lgw_start();if (i == LGW_HAL_SUCCESS) {MSG("INFO: [main] concentrator started, packet can now be received\n");}else {MSG("ERROR: [main] failed to start the concentrator\n");exit(EXIT_FAILURE);} 首先，调用 lgw_start() 函数启动集中器，并将返回值赋给变量 i。然后检查 lgw_start() 的返回值，以确定集中器是否成功启动：
成功---调用 MSG 宏输出信息：“INFO: [main] concentrator started, packet can now be received”，通知用户集中器已经成功启动，并且可以接收数据包。
失败---调用 MSG 宏输出错误信息：“ERROR: [main] failed to start the concentrator”，通知用户启动集中器失败。然后调用 exit(EXIT_FAILURE) 退出程序，表示程序因错误退出。
三、lgw_start函数
该函数用于初始化和启动一个 LoRa 集中器设备。接下来我们来看看该函数是如何实现功能的吧！
1、检查设备是否已经启动
if (lgw_is_started == true)
{DEBUG_MSG("Note: LoRa concentrator already started, restarting it now\n");
}
2、连接到设备（lgw_connect函数下面已经整理了）
reg_stat = lgw_connect(false, rf_tx_notch_freq[rf_tx_enable[1]?1:0]);
if (reg_stat == LGW_REG_ERROR)
{DEBUG_MSG("ERROR: FAIL TO CONNECT BOARD\n");return LGW_HAL_ERROR;
}
3、重置寄存器（lgw_soft_reset函数下面已经整理了）
lgw_soft_reset();
lgw_reg_w(LGW_GLOBAL_EN, 0);
lgw_reg_w(LGW_CLK32M_EN, 0);
4、启动和重置射频电台
lgw_reg_w(LGW_RADIO_A_EN,1);
lgw_reg_w(LGW_RADIO_B_EN,1);
wait_ms(500);
lgw_reg_w(LGW_RADIO_RST,1);
wait_ms(5);
lgw_reg_w(LGW_RADIO_RST,0);
5、配置射频电台
err = lgw_setup_sx125x(0, rf_clkout, rf_enable[0], rf_radio_type[0], rf_rx_freq[0]);
if (err != 0)
{DEBUG_MSG("ERROR: Failed to setup sx125x radio for RF chain 0\n");return LGW_HAL_ERROR;
}
err = lgw_setup_sx125x(1, rf_clkout, rf_enable[1], rf_radio_type[1], rf_rx_freq[1]);
if (err != 0)
{DEBUG_MSG("ERROR: Failed to setup sx125x radio for RF chain 0\n");return LGW_HAL_ERROR;
}
6、配置外部数字滤波器
lgw_reg_w(LGW_GPIO_MODE,31);
lgw_reg_w(LGW_GPIO_SELECT_OUTPUT,2);
7、配置LBT（Listen Before Talk）功能
if (lbt_is_enabled() == true)
{lgw_reg_w(LGW_CLK32M_EN, 1);i = lbt_setup();if (i != LGW_LBT_SUCCESS) {DEBUG_MSG("ERROR: lbt_setup() did not return SUCCESS\n");return LGW_HAL_ERROR;}lgw_reg_w(LGW_CLK32M_EN, 0);i = lbt_start();if (i != LGW_LBT_SUCCESS) {DEBUG_MSG("ERROR: lbt_start() did not return SUCCESS\n");return LGW_HAL_ERROR;}
}
8、启用时钟
lgw_reg_w(LGW_GLOBAL_EN, 1);
lgw_reg_w(LGW_CLK32M_EN, 1);
9、选择和发送校准命令
cal_cmd = 0;
cal_cmd |= rf_enable[0] ? 0x01 : 0x00;
cal_cmd |= rf_enable[1] ? 0x02 : 0x00;
cal_cmd |= (rf_enable[0] && rf_tx_enable[0]) ? 0x04 : 0x00;
cal_cmd |= (rf_enable[1] && rf_tx_enable[1]) ? 0x08 : 0x00;
cal_cmd |= 0x10;switch (rf_radio_type[0]) {case LGW_RADIO_TYPE_SX1255:cal_cmd |= 0x20;break;case LGW_RADIO_TYPE_SX1257:cal_cmd |= 0x00;break;default:DEBUG_PRINTF("ERROR: UNEXPECTED VALUE %d FOR RADIO TYPE\n", rf_radio_type[0]);break;
}cal_time = 2300;
10、加载校准固件并启动MCU
load_firmware(MCU_AGC, cal_firmware, MCU_AGC_FW_BYTE);
lgw_reg_w(LGW_FORCE_HOST_RADIO_CTRL, 0);
lgw_reg_w(LGW_RADIO_SELECT, cal_cmd);
lgw_reg_w(LGW_MCU_RST_1, 0);
11、检查固件版本
lgw_reg_w(LGW_DBG_AGC_MCU_RAM_ADDR, FW_VERSION_ADDR);
lgw_reg_r(LGW_DBG_AGC_MCU_RAM_DATA, &read_val);
fw_version = (uint8_t)read_val;
if (fw_version != FW_VERSION_CAL)
{printf("ERROR: Version of calibration firmware not expected, actual:%d expected:%d\n", fw_version, FW_VERSION_CAL);return -1;
}
12、启动校准并检查校准状态
lgw_reg_w(LGW_PAGE_REG, 3);
lgw_reg_w(LGW_EMERGENCY_FORCE_HOST_CTRL, 0);
DEBUG_PRINTF("Note: calibration started (time: %u ms)\n", cal_time);
wait_ms(cal_time);
lgw_reg_w(LGW_EMERGENCY_FORCE_HOST_CTRL, 1);lgw_reg_r(LGW_MCU_AGC_STATUS, &read_val);
cal_status = (uint8_t)read_val;
if ((cal_status & 0x81) != 0x81)
{DEBUG_PRINTF("ERROR: CALIBRATION FAILURE (STATUS = %u)\n", cal_status);return LGW_HAL_ERROR;
}
13、获取和检查校准偏移值
for(i=0; i<=7; ++i)
{lgw_reg_w(LGW_DBG_AGC_MCU_RAM_ADDR, 0xA0+i);lgw_reg_r(LGW_DBG_AGC_MCU_RAM_DATA, &read_val);cal_offset_a_i[i] = (int8_t)read_val;lgw_reg_w(LGW_DBG_AGC_MCU_RAM_ADDR, 0xA8+i);lgw_reg_r(LGW_DBG_AGC_MCU_RAM_DATA, &read_val);cal_offset_a_q[i] = (int8_t)read_val;lgw_reg_w(LGW_DBG_AGC_MCU_RAM_ADDR, 0xB0+i);lgw_reg_r(LGW_DBG_AGC_MCU_RAM_DATA, &read_val);cal_offset_b_i[i] = (int8_t)read_val;lgw_reg_w(LGW_DBG_AGC_MCU_RAM_ADDR, 0xB8+i);lgw_reg_r(LGW_DBG_AGC_MCU_RAM_DATA, &read_val);cal_offset_b_q[i] = (int8_t)read_val;
}
14、调整常数并配置频率漂移
lgw_constant_adjust();
x = 4096000000 / (rf_rx_freq[0] >> 1);
x = ( x > 63 ) ? 63 : x;
lgw_reg_w(LGW_FREQ_TO_TIME_DRIFT, x);x = 4096000000 / (rf_rx_freq[0] >> 3);
x = ( x > 63 ) ? 63 : x;
lgw_reg_w(LGW_MBWSSF_FREQ_TO_TIME_DRIFT, x);
15、配置LoRa多通道解调器
radio_select = 0;
for(i=0; i<LGW_MULTI_NB; ++i)
{radio_select += (if_rf_chain[i] == 1 ? 1 << i : 0);
}
16、配置LoRa单独解调器
lgw_reg_w(LGW_IF_FREQ_8, IF_HZ_TO_REG(if_freq[8]));
if (if_enable[8] == true) {lgw_reg_w(LGW_MBWSSF_RADIO_SELECT, if_rf_chain[8]);switch(lora_rx_bw) {case BW_125KHZ: lgw_reg_w(LGW_MBWSSF_MODEM_BW, 0); break;case BW_250KHZ: lgw_reg_w(LGW_MBWSSF_MODEM_BW, 1); break;case BW_500KHZ: lgw_reg_w(LGW_MBWSSF_MODEM_BW, 2); break;default:DEBUG_PRINTF("ERROR: UNEXPECTED VALUE %d IN SWITCH STATEMENT\n", lora_rx_bw);return LGW_HAL_ERROR;}switch(lora_rx_sf) {case DR_LORA_SF7: lgw_reg_w(LGW_MBWSSF_RATE_SF, 7); break;case DR_LORA_SF8: lgw_reg_w(LGW_MBWSSF_RATE_SF, 8); break;case DR_LORA_SF9: lgw_reg_w(LGW_MBWSSF_RATE_SF, 9); break;
四、lgw_connect函数
这段代码主要用于连接 LoRa 集中器，并且在连接成功后进行一些初始化操作。以下是代码的详细解释：
代码主干部分
int lgw_connect(bool spi_only, uint32_t tx_notch_freq)
{int spi_stat = LGW_SPI_SUCCESS;uint8_t u = 0;int x;/* check SPI link status */if (lgw_spi_target != NULL) {DEBUG_MSG("WARNING: concentrator was already connected\n");lgw_spi_close(lgw_spi_target);}/* open the SPI link */spi_stat = lgw_spi_open(&lgw_spi_target);if (spi_stat != LGW_SPI_SUCCESS) {DEBUG_MSG("ERROR CONNECTING CONCENTRATOR\n");return LGW_REG_ERROR;}
lgw_connect函数接受两个参数：spi_only表示是否仅使用 SPI，tx_notch_freq是传输时的不可用频率。- 首先，代码检查当前的 SPI 链接状态，如果已经连接了集中器，则关闭当前连接。
- 然后，尝试打开 SPI 链接，如果打开失败，则输出错误信息并返回错误代码
LGW_REG_ERROR。
if (spi_only == false ) {/* Detect if the gateway has an FPGA with SPI mux header support *//* First, we assume there is an FPGA, and try to read its version */spi_stat = lgw_spi_r(lgw_spi_target, LGW_SPI_MUX_MODE1, LGW_SPI_MUX_TARGET_FPGA, loregs[LGW_VERSION].addr, &u);if (spi_stat != LGW_SPI_SUCCESS) {DEBUG_MSG("ERROR READING VERSION REGISTER\n");return LGW_REG_ERROR;}if (check_fpga_version(u) != true) {/* We failed to read expected FPGA version, so let's assume there is no FPGA */DEBUG_PRINTF("INFO: no FPGA detected or version not supported (v%u)\n", u);lgw_spi_mux_mode = LGW_SPI_MUX_MODE0;} else {DEBUG_PRINTF("INFO: detected FPGA with SPI mux header (v%u)\n", u);lgw_spi_mux_mode = LGW_SPI_MUX_MODE1;/* FPGA Soft Reset */lgw_spi_w(lgw_spi_target, lgw_spi_mux_mode, LGW_SPI_MUX_TARGET_FPGA, 0, 1);lgw_spi_w(lgw_spi_target, lgw_spi_mux_mode, LGW_SPI_MUX_TARGET_FPGA, 0, 0);/* FPGA configure */x = lgw_fpga_configure(tx_notch_freq);if (x != LGW_REG_SUCCESS) {DEBUG_MSG("ERROR CONFIGURING FPGA\n");return LGW_REG_ERROR;}}/* check SX1301 version */spi_stat = lgw_spi_r(lgw_spi_target, lgw_spi_mux_mode, LGW_SPI_MUX_TARGET_SX1301, loregs[LGW_VERSION].addr, &u);if (spi_stat != LGW_SPI_SUCCESS) {DEBUG_MSG("ERROR READING CHIP VERSION REGISTER\n");return LGW_REG_ERROR;}if (u != loregs[LGW_VERSION].dflt) {DEBUG_PRINTF("ERROR: NOT EXPECTED CHIP VERSION (v%u)\n", u);return LGW_REG_ERROR;}/* write 0 to the page/reset register */spi_stat = lgw_spi_w(lgw_spi_target, lgw_spi_mux_mode, LGW_SPI_MUX_TARGET_SX1301, loregs[LGW_PAGE_REG].addr, 0);if (spi_stat != LGW_SPI_SUCCESS) {DEBUG_MSG("ERROR WRITING PAGE REGISTER\n");return LGW_REG_ERROR;} else {lgw_regpage = 0;}}
如果 spi_only 参数为 false，则执行以下操作：
- 检测网关是否具有带有 SPI 复用器头的 FPGA 支持。
- 尝试读取 FPGA 版本，如果成功读取到版本号则进行 FPGA 的软复位和配置。
- 检查 SX1301 芯片的版本号，并且确保版本号与期望的版本号相符。
- 将值 0 写入页/复位寄存器，以重置寄存器页为默认页。
DEBUG_MSG("Note: success connecting the concentrator\n");return LGW_REG_SUCCESS;
}
最后，在成功连接集中器后输出成功信息，并返回 LGW_REG_SUCCESS 表示连接成功。
五、lgw_soft_reset函数
这个函数实现了软重置功能，用于重置集中器模块。
1、检查SPI连接
if ((lgw_spi_target == NULL) || (lgw_regpage < 0))
{DEBUG_MSG("ERROR: CONCENTRATOR UNCONNECTED\n");return LGW_REG_ERROR;
}
这里首先检查了是否已经初始化了 SPI 连接，并且检查了是否已经设置了正确的寄存器页（lgw_regpage）。如果 SPI 连接未初始化或者寄存器页设置不正确，就会打印错误消息并返回 LGW_REG_ERROR。
2、发送软重置命令
lgw_spi_w(lgw_spi_target, lgw_spi_mux_mode, LGW_SPI_MUX_TARGET_SX1301, 0, 0x80); /* 1 -> SOFT_RESET bit */
这行代码向 SX1301 芯片的指定目标（LGW_SPI_MUX_TARGET_SX1301）发送一个特定的命令字节，其中第 7 位被设置为 1，表示软重置（SOFT_RESET）。这个命令将触发 SX1301 芯片执行软重置操作。
3、重置寄存器页
lgw_regpage = 0; /* reset the paging static variable */
4、返回执行结果
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