fix(rs485): 频率从原始 capvd 直接计算，不再依赖 BLE 报告通道

rs485_get_freq(): 用 g_loop_acs_info.loop_capvd + loop1_LPCNT 直接算
freq = FREQ_SYS * LPCNT / capvd + 360

之前 g_loop_acs_info.frequent 只在 usart_packet_processing_acs_loop
里赋值，该路径被 g_dbn_ble_state_acs_enable.enable 门控，
BLE 断开时 freq 永远为 0

BLE/DLD154Pro_Peripheral_28K/APP/rs485_700bs.c

@@ -13,6 +13,7 @@
 #include "cmcng.h"
 #include "rs485_700bs.h"
 #include "storage.h"
+#include "dbn_ble_srv.h"
 #include <string.h>
 
 /*===========================================================================
@@ -86,6 +87,15 @@ static void rs485_send(const uint8_t *data, uint8_t len)
  * 命令处理
  *===========================================================================*/
 
+/* 直接从原始测量值计算线圈频率 (Hz)，不依赖 BLE 报告通道 */
+static uint32_t rs485_get_freq(void)
+{
+    uint32_t capvd = g_loop_acs_info.loop_capvd;  // TMR0 捕获累加值
+    if (capvd == 0 || loop1_LPCNT == 0) return 0;
+    /* freq = FREQ_SYS / (capvd / LPCNT) + 360 (补偿值) */
+    return (uint32_t)((uint64_t)FREQ_SYS * loop1_LPCNT / capvd) + 360;
+}
+
 /* 0xFA — 查询有车状态 + 线圈好坏 */
 static void handle_query_status(uint8_t addr)
 {
@@ -100,7 +110,7 @@ static void handle_query_status(uint8_t addr)
 /* 0x1B — 查询线圈频率 */
 static void handle_query_freq(uint8_t addr)
 {
-    uint32_t freq = g_loop_acs_info.frequent;  // Hz
+    uint32_t freq = rs485_get_freq();  // Hz
     uint8_t buf[6];
     buf[0] = RSP_FREQ;
     buf[1] = (uint8_t)((freq >> 16) & 0xFF);  // Fre_1 (MSB)
@@ -166,7 +176,7 @@ static uint8_t calc_freq_err(uint32_t freq)
 static void rs485_send_heartbeat(void)
 {
     extern uint8_t loop1_LOOP_OK;
-    uint32_t freq = g_loop_acs_info.frequent;
+    uint32_t freq = rs485_get_freq();
     uint8_t  st   = g_rs485_id & 0x1F;
 
     if (g_loop_acs_info.car_state)  st |= 0x80;  // bit7=有车