diff --git a/ports/arduino_uno/apdu.c b/ports/arduino_uno/apdu.c
index ec767c89..c56e4c34 100644
--- a/ports/arduino_uno/apdu.c
+++ b/ports/arduino_uno/apdu.c
@@ -70,10 +70,10 @@ uint16_t apdu_decode_confirmed_service_request(uint8_t * apdu,  /* APDU data */
 {
     uint16_t len = 0;   /* counts where we are in PDU */
 
-    service_data->segmented_message = (apdu[0] & BIT3) ? true : false;
-    service_data->more_follows = (apdu[0] & BIT2) ? true : false;
+    service_data->segmented_message = (apdu[0] & BIT(3)) ? true : false;
+    service_data->more_follows = (apdu[0] & BIT(2)) ? true : false;
     service_data->segmented_response_accepted =
-        (apdu[0] & BIT1) ? true : false;
+        (apdu[0] & BIT(1)) ? true : false;
     service_data->max_segs = decode_max_segs(apdu[1]);
     service_data->max_resp = decode_max_apdu(apdu[1]);
     service_data->invoke_id = apdu[2];
diff --git a/ports/at91sam7s/dlmstp.c b/ports/at91sam7s/dlmstp.c
index 1644bf4f..9f08785c 100644
--- a/ports/at91sam7s/dlmstp.c
+++ b/ports/at91sam7s/dlmstp.c
@@ -274,7 +274,7 @@ static bool dlmstp_compare_data_expecting_reply(
     }
     request.invoke_id = request_pdu[offset + 2];
     /* segmented message? */
-    if (request_pdu[offset] & BIT3)
+    if (request_pdu[offset] & BIT(3))
         request.service_choice = request_pdu[offset + 5];
     else
         request.service_choice = request_pdu[offset + 3];
@@ -297,7 +297,7 @@ static bool dlmstp_compare_data_expecting_reply(
         case PDU_TYPE_COMPLEX_ACK:
             reply.invoke_id = reply_pdu[offset + 1];
             /* segmented message? */
-            if (reply_pdu[offset] & BIT3)
+            if (reply_pdu[offset] & BIT(3))
                 reply.service_choice = reply_pdu[offset + 4];
             else
                 reply.service_choice = reply_pdu[offset + 2];
diff --git a/ports/atmega168/apdu.c b/ports/atmega168/apdu.c
index 986d31d0..20df3a77 100644
--- a/ports/atmega168/apdu.c
+++ b/ports/atmega168/apdu.c
@@ -71,10 +71,10 @@ uint16_t apdu_decode_confirmed_service_request(
 {
     uint16_t len = 0;   /* counts where we are in PDU */
 
-    service_data->segmented_message = (apdu[0] & BIT3) ? true : false;
-    service_data->more_follows = (apdu[0] & BIT2) ? true : false;
+    service_data->segmented_message = (apdu[0] & BIT(3)) ? true : false;
+    service_data->more_follows = (apdu[0] & BIT(2)) ? true : false;
     service_data->segmented_response_accepted =
-        (apdu[0] & BIT1) ? true : false;
+        (apdu[0] & BIT(1)) ? true : false;
     service_data->max_segs = decode_max_segs(apdu[1]);
     service_data->max_resp = decode_max_apdu(apdu[1]);
     service_data->invoke_id = apdu[2];
diff --git a/ports/bdk-atxx4-mstp/dlmstp.c b/ports/bdk-atxx4-mstp/dlmstp.c
index 091b72f1..e58da09f 100644
--- a/ports/bdk-atxx4-mstp/dlmstp.c
+++ b/ports/bdk-atxx4-mstp/dlmstp.c
@@ -273,7 +273,7 @@ static bool dlmstp_compare_data_expecting_reply(
     }
     request.invoke_id = request_pdu[offset + 2];
     /* segmented message? */
-    if (request_pdu[offset] & BIT3)
+    if (request_pdu[offset] & BIT(3))
         request.service_choice = request_pdu[offset + 5];
     else
         request.service_choice = request_pdu[offset + 3];
@@ -296,7 +296,7 @@ static bool dlmstp_compare_data_expecting_reply(
         case PDU_TYPE_COMPLEX_ACK:
             reply.invoke_id = reply_pdu[offset + 1];
             /* segmented message? */
-            if (reply_pdu[offset] & BIT3)
+            if (reply_pdu[offset] & BIT(3))
                 reply.service_choice = reply_pdu[offset + 4];
             else
                 reply.service_choice = reply_pdu[offset + 2];
diff --git a/ports/bdk-atxx4-mstp/test.c b/ports/bdk-atxx4-mstp/test.c
index b7b2cc00..fa7e4dd6 100644
--- a/ports/bdk-atxx4-mstp/test.c
+++ b/ports/bdk-atxx4-mstp/test.c
@@ -165,13 +165,13 @@ void test_task(
         mstimer_reset(&Test_Timer);
         sprintf(Send_Buffer, "BACnet: 0000000\r\n");
         MSTP_MAC_Address = input_address();
-        Send_Buffer[8] = (MSTP_MAC_Address & BIT0) ? '1' : '0';
-        Send_Buffer[9] = (MSTP_MAC_Address & BIT1) ? '1' : '0';
-        Send_Buffer[10] = (MSTP_MAC_Address & BIT2) ? '1' : '0';
-        Send_Buffer[11] = (MSTP_MAC_Address & BIT3) ? '1' : '0';
-        Send_Buffer[12] = (MSTP_MAC_Address & BIT4) ? '1' : '0';
-        Send_Buffer[13] = (MSTP_MAC_Address & BIT5) ? '1' : '0';
-        Send_Buffer[14] = (MSTP_MAC_Address & BIT6) ? '1' : '0';
+        Send_Buffer[8] = (MSTP_MAC_Address & BIT(0)) ? '1' : '0';
+        Send_Buffer[9] = (MSTP_MAC_Address & BIT(1)) ? '1' : '0';
+        Send_Buffer[10] = (MSTP_MAC_Address & BIT(2)) ? '1' : '0';
+        Send_Buffer[11] = (MSTP_MAC_Address & BIT(3)) ? '1' : '0';
+        Send_Buffer[12] = (MSTP_MAC_Address & BIT(4)) ? '1' : '0';
+        Send_Buffer[13] = (MSTP_MAC_Address & BIT(5)) ? '1' : '0';
+        Send_Buffer[14] = (MSTP_MAC_Address & BIT(6)) ? '1' : '0';
         serial_bytes_send((uint8_t *) Send_Buffer, 17);
     }
     if (serial_byte_get(&data_register)) {
diff --git a/ports/linux/dlmstp.c b/ports/linux/dlmstp.c
index 0cc87eb0..cea55170 100644
--- a/ports/linux/dlmstp.c
+++ b/ports/linux/dlmstp.c
@@ -447,7 +447,7 @@ static bool dlmstp_compare_data_expecting_reply(
     }
     request.invoke_id = request_pdu[offset + 2];
     /* segmented message? */
-    if (request_pdu[offset] & BIT3) {
+    if (request_pdu[offset] & BIT(3)) {
         request.service_choice = request_pdu[offset + 5];
     } else {
         request.service_choice = request_pdu[offset + 3];
@@ -475,7 +475,7 @@ static bool dlmstp_compare_data_expecting_reply(
         case PDU_TYPE_COMPLEX_ACK:
             reply.invoke_id = reply_pdu[offset + 1];
             /* segmented message? */
-            if (reply_pdu[offset] & BIT3) {
+            if (reply_pdu[offset] & BIT(3)) {
                 reply.service_choice = reply_pdu[offset + 4];
             } else {
                 reply.service_choice = reply_pdu[offset + 2];
diff --git a/ports/linux/dlmstp_linux.c b/ports/linux/dlmstp_linux.c
index bbdad1ab..f97b5c67 100644
--- a/ports/linux/dlmstp_linux.c
+++ b/ports/linux/dlmstp_linux.c
@@ -444,7 +444,7 @@ bool dlmstp_compare_data_expecting_reply(
     }
     request.invoke_id = request_pdu[offset + 2];
     /* segmented message? */
-    if (request_pdu[offset] & BIT3) {
+    if (request_pdu[offset] & BIT(3)) {
         request.service_choice = request_pdu[offset + 5];
     } else {
         request.service_choice = request_pdu[offset + 3];
@@ -472,7 +472,7 @@ bool dlmstp_compare_data_expecting_reply(
         case PDU_TYPE_COMPLEX_ACK:
             reply.invoke_id = reply_pdu[offset + 1];
             /* segmented message? */
-            if (reply_pdu[offset] & BIT3) {
+            if (reply_pdu[offset] & BIT(3)) {
                 reply.service_choice = reply_pdu[offset + 4];
             } else {
                 reply.service_choice = reply_pdu[offset + 2];
diff --git a/ports/pic18f6720/apdu.c b/ports/pic18f6720/apdu.c
index 004ca63a..85005fe8 100644
--- a/ports/pic18f6720/apdu.c
+++ b/ports/pic18f6720/apdu.c
@@ -85,10 +85,10 @@ uint16_t apdu_decode_confirmed_service_request(
 {
     uint16_t len = 0;   /* counts where we are in PDU */
 
-    service_data->segmented_message = (apdu[0] & BIT3) ? true : false;
-    service_data->more_follows = (apdu[0] & BIT2) ? true : false;
+    service_data->segmented_message = (apdu[0] & BIT(3)) ? true : false;
+    service_data->more_follows = (apdu[0] & BIT(2)) ? true : false;
     service_data->segmented_response_accepted =
-        (apdu[0] & BIT1) ? true : false;
+        (apdu[0] & BIT(1)) ? true : false;
     service_data->max_segs = decode_max_segs(apdu[1]);
     service_data->max_resp = decode_max_apdu(apdu[1]);
     service_data->invoke_id = apdu[2];
diff --git a/ports/pic18f6720/mstp.c b/ports/pic18f6720/mstp.c
index 13d41792..02e53493 100644
--- a/ports/pic18f6720/mstp.c
+++ b/ports/pic18f6720/mstp.c
@@ -590,7 +590,7 @@ static bool mstp_compare_data_expecting_reply(
     }
     request.invoke_id = request_pdu[offset + 2];
     /* segmented message? */
-    if (request_pdu[offset] & BIT3)
+    if (request_pdu[offset] & BIT(3))
         request.service_choice = request_pdu[offset + 5];
     else
         request.service_choice = request_pdu[offset + 3];
@@ -613,7 +613,7 @@ static bool mstp_compare_data_expecting_reply(
         case PDU_TYPE_COMPLEX_ACK:
             reply.invoke_id = reply_pdu[offset + 1];
             /* segmented message? */
-            if (reply_pdu[offset] & BIT3)
+            if (reply_pdu[offset] & BIT(3))
                 reply.service_choice = reply_pdu[offset + 4];
             else
                 reply.service_choice = reply_pdu[offset + 2];
diff --git a/ports/pic18f97j60/apdu.c b/ports/pic18f97j60/apdu.c
index 004ca63a..85005fe8 100644
--- a/ports/pic18f97j60/apdu.c
+++ b/ports/pic18f97j60/apdu.c
@@ -85,10 +85,10 @@ uint16_t apdu_decode_confirmed_service_request(
 {
     uint16_t len = 0;   /* counts where we are in PDU */
 
-    service_data->segmented_message = (apdu[0] & BIT3) ? true : false;
-    service_data->more_follows = (apdu[0] & BIT2) ? true : false;
+    service_data->segmented_message = (apdu[0] & BIT(3)) ? true : false;
+    service_data->more_follows = (apdu[0] & BIT(2)) ? true : false;
     service_data->segmented_response_accepted =
-        (apdu[0] & BIT1) ? true : false;
+        (apdu[0] & BIT(1)) ? true : false;
     service_data->max_segs = decode_max_segs(apdu[1]);
     service_data->max_resp = decode_max_apdu(apdu[1]);
     service_data->invoke_id = apdu[2];
diff --git a/ports/pic18f97j60/mstp.c b/ports/pic18f97j60/mstp.c
index 87f14752..83fa3e4e 100644
--- a/ports/pic18f97j60/mstp.c
+++ b/ports/pic18f97j60/mstp.c
@@ -590,7 +590,7 @@ static bool mstp_compare_data_expecting_reply(
     }
     request.invoke_id = request_pdu[offset + 2];
     /* segmented message? */
-    if (request_pdu[offset] & BIT3)
+    if (request_pdu[offset] & BIT(3))
         request.service_choice = request_pdu[offset + 5];
     else
         request.service_choice = request_pdu[offset + 3];
@@ -609,7 +609,7 @@ static bool mstp_compare_data_expecting_reply(
         case PDU_TYPE_CONFIRMED_SERVICE_REQUEST:
             reply.invoke_id = reply_pdu[offset + 2];
             /* segmented message? */
-            if (reply_pdu[offset] & BIT3)
+            if (reply_pdu[offset] & BIT(3))
                 reply.service_choice = reply_pdu[offset + 5];
             else
                 reply.service_choice = reply_pdu[offset + 3];
@@ -621,7 +621,7 @@ static bool mstp_compare_data_expecting_reply(
         case PDU_TYPE_COMPLEX_ACK:
             reply.invoke_id = reply_pdu[offset + 1];
             /* segmented message? */
-            if (reply_pdu[offset] & BIT3)
+            if (reply_pdu[offset] & BIT(3))
                 reply.service_choice = reply_pdu[offset + 4];
             else
                 reply.service_choice = reply_pdu[offset + 2];
diff --git a/ports/stm32f10x/dlmstp.c b/ports/stm32f10x/dlmstp.c
index 9aed5e69..58830d60 100644
--- a/ports/stm32f10x/dlmstp.c
+++ b/ports/stm32f10x/dlmstp.c
@@ -277,7 +277,7 @@ static bool dlmstp_compare_data_expecting_reply(
     }
     request.invoke_id = request_pdu[offset + 2];
     /* segmented message? */
-    if (request_pdu[offset] & BIT3)
+    if (request_pdu[offset] & BIT(3))
         request.service_choice = request_pdu[offset + 5];
     else
         request.service_choice = request_pdu[offset + 3];
@@ -300,7 +300,7 @@ static bool dlmstp_compare_data_expecting_reply(
         case PDU_TYPE_COMPLEX_ACK:
             reply.invoke_id = reply_pdu[offset + 1];
             /* segmented message? */
-            if (reply_pdu[offset] & BIT3)
+            if (reply_pdu[offset] & BIT(3))
                 reply.service_choice = reply_pdu[offset + 4];
             else
                 reply.service_choice = reply_pdu[offset + 2];
diff --git a/ports/win32/dlmstp-mm.c b/ports/win32/dlmstp-mm.c
index 1cfd5543..95009b09 100644
--- a/ports/win32/dlmstp-mm.c
+++ b/ports/win32/dlmstp-mm.c
@@ -350,7 +350,7 @@ bool dlmstp_compare_data_expecting_reply(
     }
     request.invoke_id = request_pdu[offset + 2];
     /* segmented message? */
-    if (request_pdu[offset] & BIT3)
+    if (request_pdu[offset] & BIT(3))
         request.service_choice = request_pdu[offset + 5];
     else
         request.service_choice = request_pdu[offset + 3];
@@ -372,7 +372,7 @@ bool dlmstp_compare_data_expecting_reply(
         case PDU_TYPE_COMPLEX_ACK:
             reply.invoke_id = reply_pdu[offset + 1];
             /* segmented message? */
-            if (reply_pdu[offset] & BIT3)
+            if (reply_pdu[offset] & BIT(3))
                 reply.service_choice = reply_pdu[offset + 4];
             else
                 reply.service_choice = reply_pdu[offset + 2];
diff --git a/ports/win32/dlmstp.c b/ports/win32/dlmstp.c
index bf81a64e..3dabef1e 100644
--- a/ports/win32/dlmstp.c
+++ b/ports/win32/dlmstp.c
@@ -334,7 +334,7 @@ static bool dlmstp_compare_data_expecting_reply(
     }
     request.invoke_id = request_pdu[offset + 2];
     /* segmented message? */
-    if (request_pdu[offset] & BIT3)
+    if (request_pdu[offset] & BIT(3))
         request.service_choice = request_pdu[offset + 5];
     else
         request.service_choice = request_pdu[offset + 3];
@@ -357,7 +357,7 @@ static bool dlmstp_compare_data_expecting_reply(
         case PDU_TYPE_COMPLEX_ACK:
             reply.invoke_id = reply_pdu[offset + 1];
             /* segmented message? */
-            if (reply_pdu[offset] & BIT3)
+            if (reply_pdu[offset] & BIT(3))
                 reply.service_choice = reply_pdu[offset + 4];
             else
                 reply.service_choice = reply_pdu[offset + 2];
diff --git a/ports/xplained/dlmstp.c b/ports/xplained/dlmstp.c
index 5938c4fc..6a1cd0ee 100644
--- a/ports/xplained/dlmstp.c
+++ b/ports/xplained/dlmstp.c
@@ -253,7 +253,7 @@ static bool dlmstp_compare_data_expecting_reply(uint8_t * request_pdu,
     }
     request.invoke_id = request_pdu[offset + 2];
     /* segmented message? */
-    if (request_pdu[offset] & BIT3)
+    if (request_pdu[offset] & BIT(3))
         request.service_choice = request_pdu[offset + 5];
     else
         request.service_choice = request_pdu[offset + 3];
diff --git a/src/bacnet/bacdcode.c b/src/bacnet/bacdcode.c
index 7f05ff61..cbc3c44e 100644
--- a/src/bacnet/bacdcode.c
+++ b/src/bacnet/bacdcode.c
@@ -216,7 +216,7 @@ int encode_tag(uint8_t *apdu,
 
     apdu[0] = 0;
     if (context_specific) {
-        apdu[0] = BIT3;
+        apdu[0] = BIT(3);
     }
 
     /* additional tag byte after this byte */
@@ -256,7 +256,7 @@ int encode_opening_tag(uint8_t *apdu, uint8_t tag_number)
     int len = 1;
 
     /* set class field to context specific */
-    apdu[0] = BIT3;
+    apdu[0] = BIT(3);
     /* additional tag byte after this byte for extended tag byte */
     if (tag_number <= 14) {
         apdu[0] |= (tag_number << 4);
@@ -278,7 +278,7 @@ int encode_closing_tag(uint8_t *apdu, uint8_t tag_number)
     int len = 1;
 
     /* set class field to context specific */
-    apdu[0] = BIT3;
+    apdu[0] = BIT(3);
     /* additional tag byte after this byte for extended tag byte */
     if (tag_number <= 14) {
         apdu[0] |= (tag_number << 4);
@@ -595,29 +595,29 @@ static uint8_t byte_reverse_bits(uint8_t in_byte)
 {
     uint8_t out_byte = 0;
 
-    if (in_byte & BIT0) {
-        out_byte |= BIT7;
+    if (in_byte & BIT(0)) {
+        out_byte |= BIT(7);
     }
-    if (in_byte & BIT1) {
-        out_byte |= BIT6;
+    if (in_byte & BIT(1)) {
+        out_byte |= BIT(6);
     }
-    if (in_byte & BIT2) {
-        out_byte |= BIT5;
+    if (in_byte & BIT(2)) {
+        out_byte |= BIT(5);
     }
-    if (in_byte & BIT3) {
-        out_byte |= BIT4;
+    if (in_byte & BIT(3)) {
+        out_byte |= BIT(4);
     }
-    if (in_byte & BIT4) {
-        out_byte |= BIT3;
+    if (in_byte & BIT(4)) {
+        out_byte |= BIT(3);
     }
-    if (in_byte & BIT5) {
-        out_byte |= BIT2;
+    if (in_byte & BIT(5)) {
+        out_byte |= BIT(2);
     }
-    if (in_byte & BIT6) {
-        out_byte |= BIT1;
+    if (in_byte & BIT(6)) {
+        out_byte |= BIT(1);
     }
-    if (in_byte & BIT7) {
-        out_byte |= BIT0;
+    if (in_byte & BIT(7)) {
+        out_byte |= BIT(0);
     }
 
     return out_byte;
@@ -2522,7 +2522,7 @@ static void testBACDCodeTags(Test *pTest)
             test_len = get_apdu_len(IS_EXTENDED_TAG_NUMBER(apdu[0]), value);
             ct_test(pTest, len == test_len);
             /* stop at the the last value */
-            if (value & BIT31) {
+            if (value & BIT(31L)) {
                 break;
             }
         }
diff --git a/src/bacnet/bacdcode.h b/src/bacnet/bacdcode.h
index f528f602..374cbd73 100644
--- a/src/bacnet/bacdcode.h
+++ b/src/bacnet/bacdcode.h
@@ -508,7 +508,7 @@ extern "C" {
 
 /* from clause 20.2.1.1 Class */
 /* true if the tag is context specific */
-#define IS_CONTEXT_SPECIFIC(x) ((x & BIT3) == BIT3)
+#define IS_CONTEXT_SPECIFIC(x) ((x & BIT(3)) == BIT(3))
 
 /* from clause 20.2.1.3.2 Constructed Data */
 /* true if the tag is an opening tag */
diff --git a/src/bacnet/bits.h b/src/bacnet/bits.h
index cf10533f..e4b1253b 100644
--- a/src/bacnet/bits.h
+++ b/src/bacnet/bits.h
@@ -27,54 +27,39 @@
 /********************************************************************
 * Bit Masks
 *********************************************************************/
-#define BIT(x)        (1<<(x))
-#define BIT0            (0x01)
-#define BIT1            (0x02)
-#define BIT2            (0x04)
-#define BIT3            (0x08)
-#define BIT4            (0x10)
-#define BIT5            (0x20)
-#define BIT6            (0x40)
-#define BIT7            (0x80)
-#define BIT8          (0x0100)
-#define BIT9          (0x0200)
-#define BIT10         (0x0400)
-#define BIT11         (0x0800)
-#define BIT12         (0x1000)
-#define BIT13         (0x2000)
-#define BIT14         (0x4000)
-#define BIT15         (0x8000)
-#define BIT16       (0x010000UL)
-#define BIT17       (0x020000UL)
-#define BIT18       (0x040000UL)
-#define BIT19       (0x080000UL)
-#define BIT20       (0x100000UL)
-#define BIT21       (0x200000UL)
-#define BIT22       (0x400000UL)
-#define BIT23       (0x800000UL)
-#define BIT24     (0x01000000UL)
-#define BIT25     (0x02000000UL)
-#define BIT26     (0x04000000UL)
-#define BIT27     (0x08000000UL)
-#define BIT28     (0x10000000UL)
-#define BIT29     (0x20000000UL)
-#define BIT30     (0x40000000UL)
-#define BIT31     (0x80000000UL)
+#ifndef BIT
+#define BIT(x)  (1<<(x))
+#endif
+#ifndef _BV
+#define _BV(x)  (1<<(x))
+#endif
 
 /* a=register, b=bit number to act upon 0-n */
+#ifndef BIT_SET
 #define BIT_SET(a,b) ((a) |= (1<<(b)))
+#endif
+#ifndef BIT_CLEAR
 #define BIT_CLEAR(a,b) ((a) &= ~(1<<(b)))
+#endif
+#ifndef BIT_FLIP
 #define BIT_FLIP(a,b) ((a) ^= (1<<(b)))
+#endif
+#ifndef BIT_CHECK
 #define BIT_CHECK(a,b) ((a) & (1<<(b)))
+#endif
 
 /* x=target variable, y=mask */
+#ifndef BITMASK_SET
 #define BITMASK_SET(x,y) ((x) |= (y))
+#endif
+#ifndef BITMASK_CLEAR
 #define BITMASK_CLEAR(x,y) ((x) &= (~(y)))
+#endif
+#ifndef BITMASK_FLIP
 #define BITMASK_FLIP(x,y) ((x) ^= (y))
+#endif
+#ifndef BITMASK_CHECK
 #define BITMASK_CHECK(x,y) (((x) & (y)) == (y))
-
-#ifndef _BV
-#define _BV(x) (1<<(x))
 #endif
 
 #endif
diff --git a/src/bacnet/npdu.c b/src/bacnet/npdu.c
index fb3cc6e1..848c279b 100644
--- a/src/bacnet/npdu.c
+++ b/src/bacnet/npdu.c
@@ -144,7 +144,7 @@ int npdu_encode_pdu(uint8_t *npdu,
         /*        0 indicates that the NSDU contains a BACnet APDU. */
         /*          Message Type field is absent. */
         if (npdu_data->network_layer_message) {
-            npdu[1] |= BIT7;
+            npdu[1] |= BIT(7);
         }
         /*Bit 6: Reserved. Shall be zero. */
         /*Bit 5: Destination specifier where: */
@@ -153,7 +153,7 @@ int npdu_encode_pdu(uint8_t *npdu,
         /* DLEN = 0 denotes broadcast MAC DADR and DADR field is absent */
         /* DLEN > 0 specifies length of DADR field */
         if (dest && dest->net) {
-            npdu[1] |= BIT5;
+            npdu[1] |= BIT(5);
         }
         /* Bit 4: Reserved. Shall be zero. */
         /* Bit 3: Source specifier where: */
@@ -162,7 +162,7 @@ int npdu_encode_pdu(uint8_t *npdu,
         /* SLEN = 0 Invalid */
         /* SLEN > 0 specifies length of SADR field */
         if (src && src->net && src->len) {
-            npdu[1] |= BIT3;
+            npdu[1] |= BIT(3);
         }
         /* Bit 2: The value of this bit corresponds to the */
         /* data_expecting_reply parameter in the N-UNITDATA primitives. */
@@ -173,7 +173,7 @@ int npdu_encode_pdu(uint8_t *npdu,
         /* a segment of a BACnet-ComplexACK-PDU, */
         /* or a network layer message expecting a reply is present. */
         if (npdu_data->data_expecting_reply) {
-            npdu[1] |= BIT2;
+            npdu[1] |= BIT(2);
         }
         /* Bits 1,0: Network priority where: */
         /* B'11' = Life Safety message */
@@ -330,7 +330,7 @@ int npdu_decode(uint8_t *npdu,
         /*          Message Type field is present. */
         /*        0 indicates that the NSDU contains a BACnet APDU. */
         /*          Message Type field is absent. */
-        npdu_data->network_layer_message = (npdu[1] & BIT7) ? true : false;
+        npdu_data->network_layer_message = (npdu[1] & BIT(7)) ? true : false;
         /*Bit 6: Reserved. Shall be zero. */
         /* Bit 4: Reserved. Shall be zero. */
         /* Bit 2: The value of this bit corresponds to data expecting reply */
@@ -341,7 +341,7 @@ int npdu_decode(uint8_t *npdu,
         /* 0 indicates that other than a BACnet-Confirmed-Request-PDU, */
         /* a segment of a BACnet-ComplexACK-PDU, */
         /* or a network layer message expecting a reply is present. */
-        npdu_data->data_expecting_reply = (npdu[1] & BIT2) ? true : false;
+        npdu_data->data_expecting_reply = (npdu[1] & BIT(2)) ? true : false;
         /* Bits 1,0: Network priority where: */
         /* B'11' = Life Safety message */
         /* B'10' = Critical Equipment message */
@@ -355,7 +355,7 @@ int npdu_decode(uint8_t *npdu,
         /* 1 = DNET, DLEN, and Hop Count present */
         /* DLEN = 0 denotes broadcast MAC DADR and DADR field is absent */
         /* DLEN > 0 specifies length of DADR field */
-        if (npdu[1] & BIT5) {
+        if (npdu[1] & BIT(5)) {
             len += decode_unsigned16(&npdu[len], &dest_net);
             /* DLEN = 0 denotes broadcast MAC DADR and DADR field is absent */
             /* DLEN > 0 specifies length of DADR field */
@@ -389,7 +389,7 @@ int npdu_decode(uint8_t *npdu,
         /* Bit 3: Source specifier where: */
         /* 0 =  SNET, SLEN, and SADR absent */
         /* 1 =  SNET, SLEN, and SADR present */
-        if (npdu[1] & BIT3) {
+        if (npdu[1] & BIT(3)) {
             len += decode_unsigned16(&npdu[len], &src_net);
             /* SLEN = 0 denotes broadcast MAC SADR and SADR field is absent */
             /* SLEN > 0 specifies length of SADR field */