diff --git a/features/FEATURE_BLE/ble/BLETypes.h b/features/FEATURE_BLE/ble/BLETypes.h
index bbe3dc2ad9..c445340e20 100644
--- a/features/FEATURE_BLE/ble/BLETypes.h
+++ b/features/FEATURE_BLE/ble/BLETypes.h
@@ -32,6 +32,16 @@
 
 namespace ble {
 
+/* replace with std::clamp when it arrives */
+template<typename T, typename R>
+void clamp(T& value, const R& min, const R& max) {
+    if (value > max) {
+        value = max;
+    } else if (value < min) {
+        value = min;
+    }
+}
+
 /**
  * Opaque reference to a connection.
  *
diff --git a/features/FEATURE_BLE/ble/gap/AdvertisingParameters.h b/features/FEATURE_BLE/ble/gap/AdvertisingParameters.h
index 5c0a563fa5..95f3229a6e 100644
--- a/features/FEATURE_BLE/ble/gap/AdvertisingParameters.h
+++ b/features/FEATURE_BLE/ble/gap/AdvertisingParameters.h
@@ -22,14 +22,6 @@
 #include "blecommon.h"
 #include "SafeEnum.h"
 
-/* TODO: std::clamp */
-#define CLAMP(value, min, max) \
-    if (value > max) { \
-        value = max; \
-    } else if (value < min) { \
-        value = min; \
-    }
-
 /**
  * @addtogroup ble
  * @{
@@ -140,11 +132,11 @@ public:
             _maxInterval = 0;
         } else if (_advType == ble::ADV_NON_CONNECTABLE_UNDIRECTED) {
             /* Min interval is slightly larger than in other modes. */
-            CLAMP(_minInterval, GAP_ADV_PARAMS_INTERVAL_MIN_NONCON, GAP_ADV_PARAMS_INTERVAL_MAX);
-            CLAMP(_maxInterval, GAP_ADV_PARAMS_INTERVAL_MIN_NONCON, GAP_ADV_PARAMS_INTERVAL_MAX);
+            ble::clamp(_minInterval, GAP_ADV_PARAMS_INTERVAL_MIN_NONCON, GAP_ADV_PARAMS_INTERVAL_MAX);
+            ble::clamp(_maxInterval, GAP_ADV_PARAMS_INTERVAL_MIN_NONCON, GAP_ADV_PARAMS_INTERVAL_MAX);
         } else {
-            CLAMP(_minInterval, GAP_ADV_PARAMS_INTERVAL_MIN, GAP_ADV_PARAMS_INTERVAL_MAX);
-            CLAMP(_maxInterval, GAP_ADV_PARAMS_INTERVAL_MIN, GAP_ADV_PARAMS_INTERVAL_MAX);
+            ble::clamp(_minInterval, GAP_ADV_PARAMS_INTERVAL_MIN, GAP_ADV_PARAMS_INTERVAL_MAX);
+            ble::clamp(_maxInterval, GAP_ADV_PARAMS_INTERVAL_MIN, GAP_ADV_PARAMS_INTERVAL_MAX);
         }
 
         /* Timeout checks. */
diff --git a/features/FEATURE_BLE/ble/gap/ExtendedConnectParameters.h b/features/FEATURE_BLE/ble/gap/ExtendedConnectParameters.h
index 810491390d..085cd1a581 100644
--- a/features/FEATURE_BLE/ble/gap/ExtendedConnectParameters.h
+++ b/features/FEATURE_BLE/ble/gap/ExtendedConnectParameters.h
@@ -59,6 +59,9 @@ public:
         _scanInterval[phy_index] = scanInterval_us / 625;
         _scanWindow[phy_index] = scanWindow_us / 625;
 
+        ble::clamp(_scanInterval[phy_index], 0x0004, 0xFFFF);
+        ble::clamp(_scanWindow[phy_index], 0x0006, 0x0C80);
+
         return *this;
     }
 
@@ -274,14 +277,14 @@ private:
     ble::scanning_policy_mode_t _filterPolicy;
     ble::own_address_type_t _ownAddressType;
 
-    uint16_t _scanInterval[MAX_PARAM_PHYS]; /* 0.625 */
-    uint16_t _scanWindow[MAX_PARAM_PHYS]; /* 0.625 */
-    uint16_t _minConnectionInterval[MAX_PARAM_PHYS]; /* 1.25 */
-    uint16_t _maxConnectionInterval[MAX_PARAM_PHYS]; /* 1.25 */
-    uint16_t _slaveLatency[MAX_PARAM_PHYS]; /* 0.625 */
-    uint16_t _connectionSupervisionTimeout[MAX_PARAM_PHYS]; /* 10 */
-    uint16_t _minEventLength[MAX_PARAM_PHYS]; /* 0.625 */
-    uint16_t _maxEventLength[MAX_PARAM_PHYS]; /* 0.625 */
+    uint16_t _scanInterval[MAX_PARAM_PHYS]; /* 0.625 ms */
+    uint16_t _scanWindow[MAX_PARAM_PHYS]; /* 0.625 ms */
+    uint16_t _minConnectionInterval[MAX_PARAM_PHYS]; /* 1.25 ms */
+    uint16_t _maxConnectionInterval[MAX_PARAM_PHYS]; /* 1.25 ms */
+    uint16_t _slaveLatency[MAX_PARAM_PHYS]; /* events */
+    uint16_t _connectionSupervisionTimeout[MAX_PARAM_PHYS]; /* 10 ms */
+    uint16_t _minEventLength[MAX_PARAM_PHYS]; /* 0.625 ms */
+    uint16_t _maxEventLength[MAX_PARAM_PHYS]; /* 0.625 ms */
 
     bool _enabledPhy[MAX_PARAM_PHYS];
 };