diff --git a/F3:F303/CANusb/can.c b/F3:F303/CANusb/can.c
index d11365a..142bfe5 100644
--- a/F3:F303/CANusb/can.c
+++ b/F3:F303/CANusb/can.c
@@ -30,7 +30,8 @@ static CAN_message messages[CAN_INMESSAGE_SIZE];
 static uint8_t first_free_idx = 0;    // index of first empty cell
 static int8_t first_nonfree_idx = -1; // index of first data cell
 static uint16_t oldspeed = 100; // speed of last init
-uint32_t floodT = FLOOD_PERIOD_MS-1; // flood period in ms
+uint32_t floodT = FLOOD_PERIOD_MS; // flood period in ms
+static uint8_t incrflood = 0; // ==1 for incremental flooding
 
 static uint32_t last_err_code = 0;
 static CAN_status can_status = CAN_STOP;
@@ -227,9 +228,13 @@ void can_proc(){
         CAN_setup(0);
     }
     static uint32_t lastFloodTime = 0;
-    if(flood_msg && (Tms - lastFloodTime) > (floodT)){ // flood every ~5ms
+    static uint32_t incrmessagectr = 0;
+    if(flood_msg && (Tms - lastFloodTime) >= floodT){ // flood every ~5ms
         lastFloodTime = Tms;
         can_send(flood_msg->data, flood_msg->length, flood_msg->ID);
+    }else if(incrflood && (Tms - lastFloodTime) >= floodT){
+        lastFloodTime = Tms;
+        if(CAN_OK == can_send((uint8_t*)&incrmessagectr, 4, flood_msg->ID)) ++incrmessagectr;
     }
 }
 
@@ -287,7 +292,9 @@ CAN_status can_send(uint8_t *msg, uint8_t len, uint16_t target_id){
     return CAN_OK;
 }
 
-void set_flood(CAN_message *msg){
+void set_flood(CAN_message *msg, int incr){
+    if(incr){ incrflood = 1; return; }
+    incrflood = 0;
     if(!msg) flood_msg = NULL;
     else{
         memcpy(&loc_flood_msg, msg, sizeof(CAN_message));
diff --git a/F3:F303/CANusb/can.h b/F3:F303/CANusb/can.h
index 1dfb6f0..87b762a 100644
--- a/F3:F303/CANusb/can.h
+++ b/F3:F303/CANusb/can.h
@@ -56,4 +56,4 @@ void printCANerr();
 
 CAN_message *CAN_messagebuf_pop();
 
-void set_flood(CAN_message *msg);
+void set_flood(CAN_message *msg, int incr);
diff --git a/F3:F303/CANusb/canusb.bin b/F3:F303/CANusb/canusb.bin
index 928e6e6..5f59866 100755
Binary files a/F3:F303/CANusb/canusb.bin and b/F3:F303/CANusb/canusb.bin differ
diff --git a/F3:F303/CANusb/main.c b/F3:F303/CANusb/main.c
index 69a883c..ffcdf3f 100644
--- a/F3:F303/CANusb/main.c
+++ b/F3:F303/CANusb/main.c
@@ -63,7 +63,7 @@ int main(void){
                 LED_on(LED0);
                 lastT = Tms;
                 if(!lastT) lastT = 1;
-                if(ShowMsgs){ // new data in buff
+                if(ShowMsgs){ // display message content
                     IWDG->KR = IWDG_REFRESH;
                     uint8_t len = can_mesg->length;
                     printu(Tms);
diff --git a/F3:F303/CANusb/proto.c b/F3:F303/CANusb/proto.c
index a4c90ac..da95efe 100644
--- a/F3:F303/CANusb/proto.c
+++ b/F3:F303/CANusb/proto.c
@@ -199,11 +199,11 @@ TRUE_INLINE void setfloodt(const char *s){
     uint32_t N;
     s = omit_spaces(s);
     const char *n = getnum(s, &N);
-    if(s == n || N == 0){
+    if(s == n){
         USB_sendstr("t="); printu(floodT); USB_putbyte('\n');
         return;
     }
-    floodT = N - 1;
+    floodT = N;
 }
 
 /**
@@ -307,6 +307,7 @@ const char *helpstring =
     "'e' - get CAN errcodes\n"
     "'f' - add/delete filter, format: bank# FIFO# mode(M/I) num0 [num1 [num2 [num3]]]\n"
     "'F' - send/clear flood message: F ID byte0 ... byteN\n"
+    "'i' - send incremental flood message (ID == ID for `F`)\n"
     "'I' - reinit CAN\n"
     "'l' - list all active filters\n"
     "'o' - turn LEDs OFF\n"
@@ -315,7 +316,7 @@ const char *helpstring =
     "'P' - pause/resume in packets displaying\n"
     "'R' - software reset\n"
     "'s/S' - send data over CAN: s ID byte0 .. byteN\n"
-    "'t' - change flood period (>=1ms)\n"
+    "'t' - change flood period (>=0ms)\n"
     "'T' - get time from start (ms)\n"
 ;
 
@@ -356,7 +357,7 @@ void cmd_parser(char *txt){
             goto eof;
         break;
         case 'F':
-            set_flood(parseCANmsg(txt));
+            set_flood(parseCANmsg(txt), 0);
             goto eof;
         break;
         case 's':
@@ -380,6 +381,10 @@ void cmd_parser(char *txt){
         case 'e':
             printCANerr();
         break;
+        case 'i':
+            set_flood(NULL, 1);
+            USB_sendstr("Incremental flooding is ON ('F' to off)\n");
+        break;
         case 'I':
             CAN_reinit(0);
         break;
diff --git a/F3:F303/CANusb/version.inc b/F3:F303/CANusb/version.inc
index 27666b7..c290d35 100644
--- a/F3:F303/CANusb/version.inc
+++ b/F3:F303/CANusb/version.inc
@@ -1,2 +1,2 @@
-#define BUILD_NUMBER "15"
+#define BUILD_NUMBER "18"
 #define BUILD_DATE "2023-01-30"