diff --git a/F1:F103/FX3U/fx3u.bin b/F1:F103/FX3U/fx3u.bin
new file mode 100755
index 0000000..045d90a
Binary files /dev/null and b/F1:F103/FX3U/fx3u.bin differ
diff --git a/F1:F103/FX3U/fx3u.creator.user b/F1:F103/FX3U/fx3u.creator.user
index 2d3fcea..dc4772c 100644
--- a/F1:F103/FX3U/fx3u.creator.user
+++ b/F1:F103/FX3U/fx3u.creator.user
@@ -1,6 +1,6 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <!DOCTYPE QtCreatorProject>
-<!-- Written by QtCreator 12.0.2, 2024-03-05T15:35:05. -->
+<!-- Written by QtCreator 13.0.1, 2024-05-30T20:03:33. -->
 <qtcreator>
  <data>
   <variable>EnvironmentId</variable>
@@ -106,8 +106,8 @@
       <value type="QString" key="ProjectExplorer.ProjectConfiguration.Id">GenericProjectManager.GenericMakeStep</value>
      </valuemap>
      <value type="qlonglong" key="ProjectExplorer.BuildStepList.StepsCount">1</value>
-     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DefaultDisplayName">Сборка</value>
-     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DisplayName">Сборка</value>
+     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DefaultDisplayName">Build</value>
+     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DisplayName">Build</value>
      <value type="QString" key="ProjectExplorer.ProjectConfiguration.Id">ProjectExplorer.BuildSteps.Build</value>
     </valuemap>
     <valuemap type="QVariantMap" key="ProjectExplorer.BuildConfiguration.BuildStepList.1">
@@ -119,8 +119,8 @@
       <value type="QString" key="ProjectExplorer.ProjectConfiguration.Id">GenericProjectManager.GenericMakeStep</value>
      </valuemap>
      <value type="qlonglong" key="ProjectExplorer.BuildStepList.StepsCount">1</value>
-     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DefaultDisplayName">Очистка</value>
-     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DisplayName">Очистка</value>
+     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DefaultDisplayName">Clean</value>
+     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DisplayName">Clean</value>
      <value type="QString" key="ProjectExplorer.ProjectConfiguration.Id">ProjectExplorer.BuildSteps.Clean</value>
     </valuemap>
     <value type="int" key="ProjectExplorer.BuildConfiguration.BuildStepListCount">2</value>
@@ -135,8 +135,8 @@
    <valuemap type="QVariantMap" key="ProjectExplorer.Target.DeployConfiguration.0">
     <valuemap type="QVariantMap" key="ProjectExplorer.BuildConfiguration.BuildStepList.0">
      <value type="qlonglong" key="ProjectExplorer.BuildStepList.StepsCount">0</value>
-     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DefaultDisplayName">Развёртывание</value>
-     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DisplayName">Развёртывание</value>
+     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DefaultDisplayName">Deploy</value>
+     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DisplayName">Deploy</value>
      <value type="QString" key="ProjectExplorer.ProjectConfiguration.Id">ProjectExplorer.BuildSteps.Deploy</value>
     </valuemap>
     <value type="int" key="ProjectExplorer.BuildConfiguration.BuildStepListCount">1</value>
@@ -155,6 +155,7 @@
     <value type="int" key="PE.EnvironmentAspect.Base">2</value>
     <valuelist type="QVariantList" key="PE.EnvironmentAspect.Changes"/>
     <value type="bool" key="PE.EnvironmentAspect.PrintOnRun">false</value>
+    <value type="QString" key="PerfRecordArgsId">-e cpu-cycles --call-graph dwarf,4096 -F 250</value>
     <value type="QString" key="ProjectExplorer.ProjectConfiguration.DisplayName"></value>
     <value type="QString" key="ProjectExplorer.ProjectConfiguration.Id">ProjectExplorer.CustomExecutableRunConfiguration</value>
     <value type="QString" key="ProjectExplorer.RunConfiguration.BuildKey"></value>
diff --git a/F1:F103/FX3U/main.c b/F1:F103/FX3U/main.c
index 61880d3..e3a34bf 100644
--- a/F1:F103/FX3U/main.c
+++ b/F1:F103/FX3U/main.c
@@ -77,7 +77,10 @@ int main(void){
         char *str;
         int g = usart_getline(&str);
         if(g < 0) usart_send("USART IN buffer overflow!\n");
-        else if(g > 0) cmd_parser(str);
+        else if(g > 0){
+            const char *ans = cmd_parser(str);
+            if(ans) usart_send(ans);
+        }
     }
     return 0;
 }
diff --git a/F1:F103/FX3U/proto.c b/F1:F103/FX3U/proto.c
index 4b7e6b5..b50013d 100644
--- a/F1:F103/FX3U/proto.c
+++ b/F1:F103/FX3U/proto.c
@@ -28,6 +28,7 @@ flags_t flags = {
     .can_monitor = 0
 };
 
+/*
 static void printans(int res){
     if(res) usart_send("OK");
     else usart_send("FAIL");
@@ -44,11 +45,96 @@ static void isetter(int(*fn)(int32_t), char* str){
     if(str == getint(str, &d)) printans(FALSE);
     else printans(fn(d));
 }
+*/
+
+// parno - number of parameter (or -1); cargs - string with arguments (after '=') (==NULL for getter), iarg - integer argument
+static int goodstub(const char *cmd, int parno, const char *carg, int32_t iarg){
+    usart_send("cmd="); usart_send(cmd);
+    usart_send(", parno="); usart_send(i2str(parno));
+    usart_send(", args="); usart_send(carg);
+    usart_send(", intarg="); usart_send(i2str(iarg)); newline();
+    return RET_GOOD;
+}
+
+typedef struct{
+    int (*fn)(const char*, int, const char*, int32_t);
+    const char *cmd;
+    const char *help;
+} commands;
+
+static commands cmdlist[] = {
+    {goodstub, "stub", "simple stub"},
+    {NULL, "Different commands", NULL},
+//    {adcval, "ADC", "get ADCx value (without x - for all)"},
+//    {adcvoltage, "ADCv", "get ADCx voltage (without x - for all)"},
+//    {mcut, "mcut", "get MCU temperature"},
+    {NULL, NULL, NULL}
+};
+
+static void printhelp(){
+    commands *c = cmdlist;
+    usart_send("https://github.com/eddyem/stm32samples/tree/master/F1:F103/FX3U#" BUILD_NUMBER " @ " BUILD_DATE "\n");
+    while(c->cmd){
+        if(!c->fn){ // header
+            usart_send("\n    ");
+            usart_send(c->cmd);
+            usart_putchar(':');
+        }else{
+            usart_send(c->cmd);
+            usart_send(" - ");
+            usart_send(c->help);
+        }
+        newline();
+        ++c;
+    }
+}
+
+/**
+ * @brief parsecmd - parse text commands over RS-232
+ * @param str - input string
+ * @return answer code
+ */
+static int parsecmd(const char *str){
+    char cmd[CMD_MAXLEN + 1];
+    //USB_sendstr("cmd="); USB_sendstr(str); USB_sendstr("__\n");
+    if(!str || !*str) return RET_CMDNOTFOUND;
+    int i = 0;
+    while(*str > '@' && i < CMD_MAXLEN){ cmd[i++] = *str++; }
+    cmd[i] = 0;
+    int parno = -1;
+    int32_t iarg = __INT32_MAX__;
+    if(*str){
+        uint32_t N;
+        const char *nxt = getnum(str, &N);
+        if(nxt != str) parno = (int) N;
+        str = strchr(str, '=');
+        if(str){
+            str = omit_spaces(++str);
+            getint(str, &iarg);
+        }
+    }else str = NULL;
+    commands *c = cmdlist;
+    while(c->cmd){
+        if(strcmp(c->cmd, cmd) == 0){
+            if(!c->fn) return RET_CMDNOTFOUND;
+            return c->fn(cmd, parno, str, iarg);
+        }
+        ++c;
+    }
+    return RET_CMDNOTFOUND;
+}
 
 /**
  * @brief cmd_parser - command parsing
  * @param txt   - buffer with commands & data
  */
-void cmd_parser(char *txt){
-    (void)txt;
+const char *cmd_parser(const char *txt){
+    int ret = parsecmd(txt);
+    switch(ret){
+    case RET_WRONGPARNO: return "Wrong parameter number\n"; break;
+    case RET_CMDNOTFOUND: printhelp(); return NULL; break;
+    case RET_WRONGARG: return "Wrong command parameters\n"; break;
+    case RET_GOOD: return NULL; break;
+    default: return "FAIL\n"; break;
+    }
 }
diff --git a/F1:F103/FX3U/proto.h b/F1:F103/FX3U/proto.h
index 023471a..0402f29 100644
--- a/F1:F103/FX3U/proto.h
+++ b/F1:F103/FX3U/proto.h
@@ -21,7 +21,19 @@
 #include <stm32f1.h>
 #include "hardware.h"
 
-#define BUFSZ   (64)
+#ifndef _U_
+#define _U_ __attribute__((__unused__))
+#endif
+
+#define CMD_MAXLEN  (32)
+
+enum{
+    RET_WRONGPARNO = -3,     // wrong parameter number
+    RET_CMDNOTFOUND = -2,    // command not found
+    RET_WRONGARG = -1,       // wrong argument
+    RET_GOOD = 0,            // all OK
+    RET_BAD = 1              // something wrong
+};
 
 typedef struct{
     uint32_t can_monitor : 1;
@@ -36,5 +48,4 @@ extern flags_t flags;
 #define DBG(str)
 #endif
 
-
-void cmd_parser(char *buf);
+const char *cmd_parser(const char *txt);
diff --git a/F1:F103/FX3U/version.inc b/F1:F103/FX3U/version.inc
index 249941c..8c865e6 100644
--- a/F1:F103/FX3U/version.inc
+++ b/F1:F103/FX3U/version.inc
@@ -1,2 +1,2 @@
-#define BUILD_NUMBER "5"
-#define BUILD_DATE "2024-05-29"
+#define BUILD_NUMBER "20"
+#define BUILD_DATE "2024-05-30"