diff --git a/CMakeLists.txt b/CMakeLists.txt
index 62ec2bd..980e8cc 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,5 +21,6 @@ else()
     src/led.cpp
     src/temp.cpp
     src/watdog.cpp
+    src/com.cpp
   )
 endif()
diff --git a/boards/dr2501a_g070rb.overlay b/boards/dr2501a_g070rb.overlay
deleted file mode 100644
index e69de29..0000000
diff --git a/boards/use_ms.overlay b/boards/use_ms.overlay
new file mode 100644
index 0000000..4c888d1
--- /dev/null
+++ b/boards/use_ms.overlay
@@ -0,0 +1,71 @@
+&ch9438_uart0 {
+  status = "okay";
+  current-speed = <9600>;
+};
+
+&gd_sensor0 {
+  mode = "wrist";
+};
+
+&ch9438_uart1 {
+  status = "okay";
+  current-speed = <9600>;
+};
+
+&gd_sensor1 {
+  mode = "wrist";
+};
+
+&ch9438_uart2 {
+  status = "okay";
+  current-speed = <9600>;
+};
+
+&gd_sensor2 {
+  mode = "wrist";
+};
+
+&ch9438_uart3 {
+  status = "okay";
+  current-speed = <9600>;
+};
+
+&gd_sensor3 {
+  mode = "wrist";
+};
+
+&ch9438_uart4 {
+  status = "okay";
+  current-speed = <9600>;
+};
+
+&gd_sensor4 {
+  mode = "wrist";
+};
+
+&ch9438_uart5 {
+  status = "okay";
+  current-speed = <9600>;
+};
+
+&gd_sensor5 {
+  mode = "wrist";
+};
+
+&ch9438_uart6 {
+  status = "okay";
+  current-speed = <9600>;
+};
+
+&gd_sensor6 {
+  mode = "wrist";
+};
+
+&ch9438_uart7 {
+  status = "okay";
+  current-speed = <9600>;
+};
+
+&gd_sensor7 {
+  mode = "wrist";
+};
diff --git a/include/infrared.hpp b/include/infrared.hpp
index b1614ef..8d552e1 100644
--- a/include/infrared.hpp
+++ b/include/infrared.hpp
@@ -6,6 +6,7 @@
 #include <etl/tuple.h>
 #include <utility>
 #include <zephyr/device.h>
+#include <zephyr/devicetree.h>
 #include <zephyr/drivers/sensor.h>
 #include <zpp/result.hpp>
 #include <zpp/value.hpp>
@@ -71,6 +72,17 @@ public:
     return out;
   }
 
+  /* Bitmask of channels that have received at least one sample (diag). */
+  static auto GetChannelValidMask() -> uint32_t {
+    uint32_t mask = 0;
+    for (size_t id = 0; id < s_dev.size(); ++id) {
+      if (s_latest_valid[id]) {
+        mask |= (1u << id);
+      }
+    }
+    return mask;
+  }
+
 private:
   /* Per-sensor trigger handler; the channel index is a compile-time
    * constant. Runs in the UART trigger context (workqueue thread for
@@ -121,9 +133,20 @@ private:
     return ret != 0 ? zpp::error{-ENODEV} : zpp::ok();
   }
 
-#define INFRARED_DEV(node) DEVICE_DT_GET(node),
+/* Channel order: ch0~7 = CH9438 SPI-UART ports, ch8 = on-chip usart2 inner
+ * sensor. DT_FOREACH follows .dtsi soc node order (usart2 before spi2), so
+ * split by parent compatible instead of relying on node order. */
+#define INFRARED_DEV(node)                                                     \
+  COND_CODE_1(DT_NODE_HAS_COMPAT(DT_PARENT(node), wch_ch9438_uart),            \
+              (DEVICE_DT_GET(node), ), ())
+#define INFRARED_INNER_DEV(node)                                               \
+  COND_CODE_1(DT_NODE_HAS_COMPAT(DT_PARENT(node), st_stm32_usart),             \
+              (DEVICE_DT_GET(node), ), ())
   inline static etl::array s_dev{
-      DT_FOREACH_STATUS_OKAY(godtek_temp_uart, INFRARED_DEV)};
+      DT_FOREACH_STATUS_OKAY(godtek_temp_uart, INFRARED_DEV)
+          DT_FOREACH_STATUS_OKAY(godtek_temp_uart, INFRARED_INNER_DEV)};
+#undef INFRARED_DEV
+#undef INFRARED_INNER_DEV
   /* Field-level volatile caches: written by the trigger handlers, read by
    * GetMaxSensorValue. sensor_value itself cannot be volatile (no volatile
    * copy/assign), so the two 32-bit fields are cached separately. A torn
diff --git a/src/com.cpp b/src/com.cpp
new file mode 100644
index 0000000..b46796f
--- /dev/null
+++ b/src/com.cpp
@@ -0,0 +1,6 @@
+
+#include <com.hpp>
+#include <zephyr/init.h>
+static auto Init() -> int { return static_cast<int>(ther::Com::Init()); }
+
+inline SYS_INIT(Init, APPLICATION, 50);
diff --git a/src/main.cpp b/src/main.cpp
index fd9b4cb..4751dfa 100644
--- a/src/main.cpp
+++ b/src/main.cpp
@@ -1,8 +1,7 @@
 
-#include <com.hpp>
+#include <zephyr/device.h>
 #include <zephyr/kernel.h>
 auto main(void) -> int {
-  ther::Com::Init();
   printk("[main] init on %s\n", CONFIG_BOARD);
   while (1) {
     k_sleep(K_SECONDS(1));
diff --git a/src/temp.cpp b/src/temp.cpp
index 511e8a3..8d89547 100644
--- a/src/temp.cpp
+++ b/src/temp.cpp
@@ -4,6 +4,11 @@
 #include <zephyr/init.h>
 #include <zephyr/kernel.h>
 
+/* 1 = enable verbose diagnostics (per-second channel dump). */
+#ifndef APP_DEBUG_PRINT
+#define APP_DEBUG_PRINT 0
+#endif
+
 using namespace ther;
 
 /* 调试打印开关：
@@ -42,6 +47,18 @@ static void OnSendTick(struct k_work *work) {
   if (auto r = Infrared::GetMaxSensorValue(); r.ok()) {
     Com::SendTemp(r.value().second);
   }
+#if APP_DEBUG_PRINT
+  static uint32_t s_send_tick; /* diag: send counter, ~1s cadence */
+  if (++s_send_tick % 50 == 0) { /* every ~1 s */
+    const auto all = Infrared::GetAllSensorValues();
+    printk("[%s]diag tick=%u mask=0x%02X val:", MODULE, (unsigned)s_send_tick,
+           (unsigned)Infrared::GetChannelValidMask());
+    for (size_t i = 0; i < all.size(); ++i) {
+      printk(" %u=%d.%d", (unsigned)i, all[i].val1, all[i].val2);
+    }
+    printk("\n");
+  }
+#endif /* APP_DEBUG_PRINT */
   k_work_schedule(&s_send_work, K_MSEC(kPeriodSend.count()));
 }
 } // namespace
diff --git a/testcase.yaml b/testcase.yaml
index aaf757f..159f104 100644
--- a/testcase.yaml
+++ b/testcase.yaml
@@ -9,3 +9,7 @@ tests:
   sample.ntc:
     extra_configs:
       - CONFIG_SAMPLE_NTC=y
+  sample.ms:
+    extra_args:
+      - DTC_OVERLAY_FILE=boards/use_ms.overlay
+    extra_configs: