feat(spi): 添加ADC反馈命令处理

新增SPI命令类型0xC4用于ADC调试反馈，实现在GD32上采集
温度/VDDA/VIN等模拟量数据的反馈功能，并支持主动推送和被动查询模式。

feat(spi): 扩展PING命令响应格式

修改PING命令响应格式，增加APP身份信息16字节载荷，包含版本号、
启动时间、功能开关位图等信息，用于主机获取从设备详细状态。

refactor(can_feedback): 优化CAN反馈推送逻辑

改进CAN反馈推送机制，跳过编译期关闭的通道，只遍历启用的通道，
确保推送效率并避免无效操作。

feat(comm): 添加EXMC总线初始化和诊断功能

添加了EXMC总线的初始化功能，包括GPIO配置、NOR/SRAM区域参数设置，
以及总线探活机制。实现了总线可见性检测，当检测到全0或全1的挂死状态时
会返回false并输出错误信息。同时添加了printf日志输出用于调试。

refactor(esc_lan9252): 重构ESC初始化返回值

将EscLan9252::init()方法的返回类型从void改为bool，
使其能够返回EXMC总线准备状态，便于上层进行状态检查。

docs(app_spi_cmd_ping): 添加代码注释文档

为SPI命令处理相关类和方法添加详细的Doxygen风格注释文档，
提高代码可读性和维护性。

GD32E508_DCU_APP/comm/ethercat_slave.cpp

@@ -32,36 +32,72 @@ uint8_t EthercatSlave::s_alState = 0U;
 
 void EthercatSlave::init()
 {
-    EscLan9252::init();
+    printf("[ECAT][SLAVE] init: begin\r\n");
+
+    if (!EscLan9252::init()) {
+        /* EXMC 总线未就绪:无法继续读芯片 ID 与 AL 状态,统一上报 FAIL。 */
+        s_chipId   = 0U;
+        s_alState  = 0U;
+        s_escReady = false;
+        printf("[ECAT][SLAVE] init: FAIL, ESC bus not ready\r\n");
+        s_inputWriteIdx = 0U;
+        s_outputReadIdx = 0U;
+        s_periodicSeq   = 0U;
+        s_processedSeq  = 0U;
+        return;
+    }
 
     /* 第 1 层调试可观测性:读取芯片 ID 并打印 selfTest 结果 */
     s_chipId = EscLan9252::readChipId();
     const bool chipIdOk = (s_chipId == 0x87654321U);
+    printf("[ECAT][SLAVE] chip id=0x%08lX expected=0x%08lX selfTest=%s\r\n",
+           (unsigned long)s_chipId, (unsigned long)0x87654321UL,
+           chipIdOk ? "PASS" : "FAIL");
 
     /* AL 状态守卫:仅在芯片 ID 匹配时读取 AL 状态(ID 不匹配时 EXMC 可能读回 0/0xFFFF,无意义)。
      * AL ≥ SAFEOP(0x04) 才认为 SYNC0 可触发;完整 ESC 配置(SM/FMMU/AL Control/SYNC0)需 SSC 集成。 */
     s_alState = 0U;
+    uint16_t alStatusReg = 0U;   /* 0x0130:AL Status(bit0-3=state,bit8-15=AL Status Code) */
     if (chipIdOk) {
-        s_alState = (uint8_t)(EscLan9252::initOnlyReadReg(0x0130U) & 0x000FU);
+        alStatusReg   = EscLan9252::initOnlyReadReg(0x0130U);
+        s_alState     = (uint8_t)(alStatusReg & 0x000FU);
     }
+    const uint8_t alCode = (uint8_t)((alStatusReg >> 8U) & 0xFFU);
     s_escReady = chipIdOk && (s_alState >= AL_STATE_SAFEOP);
 
+    /* AL 状态码 → 可读字符串(EtherCAT 状态机定义,见 ETG.1000.6)。
+     * 0x01=INIT, 0x02=PREOP, 0x03=BOOT, 0x04=SAFEOP, 0x08=OP。
+     * 本工程 AL_STATE_SAFEOP=0x04 与官方定义一致;守卫 s_alState>=0x04,
+     * 因此 OP(0x08) 也会通过,SAFEOP(0x04) 刚好通过,BOOT/PREOP/INIT 不通过。 */
+    const char *alStateName = "UNKNOWN";
+    switch (s_alState) {
+        case 0x00U: alStateName = "NONE";    break;
+        case 0x01U: alStateName = "INIT";    break;
+        case 0x02U: alStateName = "PREOP";   break;
+        case 0x03U: alStateName = "BOOT";    break;
+        case 0x04U: alStateName = "SAFEOP";  break;
+        case 0x08U: alStateName = "OP";      break;
+        default: break;
+    }
+    /* AL Status Code(寄存器 0x0130 高 8 位):非 0 表示从站进入错误状态
+     * (如 SM Watchdog=0x1B、FMMU 配置错、邮箱协议错),需主站介入。 */
+
     if (!chipIdOk) {
-        printf("[ECAT] ESC chip id=0x%08lX selfTest=FAIL\r\n", (unsigned long)s_chipId);
-        printf("[ECAT] ESC NOT ready, sync ISR disabled (check EXMC wiring/timing)\r\n");
+        printf("[ECAT][SLAVE] ESC NOT ready, sync ISR disabled (check EXMC wiring/timing)\r\n");
     } else if (s_alState < AL_STATE_SAFEOP) {
-        printf("[ECAT] ESC chip id=0x%08lX selfTest=PASS, but AL state=0x%02X < SAFEOP(0x%02X)\r\n",
-               (unsigned long)s_chipId, (unsigned)s_alState, (unsigned)AL_STATE_SAFEOP);
-        printf("[ECAT] SYNC0 will not fire, full ESC config requires SSC integration\r\n");
+        printf("[ECAT][SLAVE] chip id PASS, but AL state=0x%02X(%s) < SAFEOP(0x%02X), code=0x%02X\r\n",
+               (unsigned)s_alState, alStateName, (unsigned)AL_STATE_SAFEOP, (unsigned)alCode);
+        printf("[ECAT][SLAVE] SYNC0 will not fire, full ESC config requires SSC integration\r\n");
     } else {
-        printf("[ECAT] ESC ready, chip id=0x%08lX, AL state=0x%02X\r\n",
-               (unsigned long)s_chipId, (unsigned)s_alState);
+        printf("[ECAT][SLAVE] ESC ready, chip id=0x%08lX, AL state=0x%02X(%s), code=0x%02X\r\n",
+               (unsigned long)s_chipId, (unsigned)s_alState, alStateName, (unsigned)alCode);
     }
 
     s_inputWriteIdx = 0U;
     s_outputReadIdx = 0U;
     s_periodicSeq = 0U;
     s_processedSeq = 0U;
+    printf("[ECAT][SLAVE] init: %s\r\n", s_escReady ? "OK" : "FAIL(partial)");
 }
 
 __attribute__((section(".ramfunc"), noinline))