perf(vd960DBN): 二轮RAM瘦身 — RECE_BUF_LEN 1024 + ARP 16 + 中断路径static (2026-08-17)

.map 分析: BLE 栈固定占 RAM 低 16KB 不可裁; 用户 48KB 内 .bss 41.7KB。
- net_config.h: RECE_BUF_LEN MSS×2(1400)→1024 (MSS=700帧+头≈740B, 5数组省~2.6KB)
- net_config.h: WCHNET_NUM_ARP_TABLE 50→16 (停车场景IP少, 省~0.8KB)
- tcp_json_srv.c: tmp_buf[RECE_BUF_LEN]/frame[800] 局部→static (中断上下文栈数组防溢出)

栈 4.7KB→~6.3KB, 中断栈峰值 -1.8KB。devlog 记录 .map 分析结论。

vd960DBN/BLE/OnlyUpdateApp_Peripheral/APP/include/net_config.h

@@ -90,7 +90,10 @@ extern "C" {
 /* If you want to achieve a higher transmission speed,
  * try to increase RECE_BUF_LEN to (WCHNET_TCP_MSS*4)
  * and increase WCHNET_NUM_TCP_SEG to (WCHNET_NUM_TCP*4)*/
-#define RECE_BUF_LEN                  (WCHNET_TCP_MSS*2)   /* socket receive buffer size */
+/* 2026-08-17 RAM 瘦身: MSS×2(1400)→1024 — MSS=700 时完整 TCP 段+头≈740B,
+   1024 足够; 5 个 RECE_BUF_LEN 数组 (SocketRecvBuf/MyBuf/tmp/_iot_wchnet_buf/
+   g_json_wchnet_buf) 合计省 ~2.6KB .bss (栈空间 +2.6KB) */
+#define RECE_BUF_LEN                  1024                  /* socket receive buffer size */
 
 #define WCHNET_NUM_PBUF               WCHNET_NUM_POOL_BUF   /* Number of PBUF structures */
 
@@ -98,7 +101,7 @@ extern "C" {
 
 #define WCHNET_MEM_HEAP_SIZE          (((WCHNET_TCP_MSS+0x10+54+8)*WCHNET_NUM_TCP_SEG)+ETH_TX_BUF_SZE+64+2*0x18) /* memory heap size */
 
-#define WCHNET_NUM_ARP_TABLE          50   /* Number of ARP lists */
+#define WCHNET_NUM_ARP_TABLE          16   /* 2026-08-17: 50→16 (停车设备同时连接 IP 少, 省 ~0.8KB .bss) */
 
 #define WCHNET_MEM_ALIGNMENT          4    /* 4 byte alignment */