New build info feature. (per @Analogreality request)

- New build info feature. Hidden command ‘$I’ will print the build info
for your Grbl firmware. Users may also write an identifying message
within it via ‘$I=‘ with up to 32 characters. (no more, or else it will
break).

- Adjusted the max number of startup lines to 3. Majority of people
will only need one.

- Fixed a compile error with spindle_control.c. A rogue #endif was
causing problems.

config.h

@@ -74,10 +74,10 @@
 #define N_HOMING_LOCATE_CYCLE 2 // Integer (1-128)
 
 // Number of blocks Grbl executes upon startup. These blocks are stored in EEPROM, where the size
-// and addresses are defined in settings.h. With the current settings, up to 5 startup blocks may
+// and addresses are defined in settings.h. With the current settings, up to 3 startup blocks may
 // be stored and executed in order. These startup blocks would typically be used to set the g-code
 // parser state depending on user preferences.
-#define N_STARTUP_LINE 2 // Integer (1-5)
+#define N_STARTUP_LINE 2 // Integer (1-3)
 
 // ---------------------------------------------------------------------------------------
 // ADVANCED CONFIGURATION OPTIONS:

protocol.c

@@ -254,6 +254,22 @@ uint8_t protocol_execute_line(char *line)
               if (!sys.abort) { protocol_execute_startup(); } // Execute startup scripts after successful homing.
             } else { return(STATUS_SETTING_DISABLED); }
             break;
+          case 'I' : // Print or store build info.
+            if ( line[++char_counter] == 0 ) { 
+              if (!(settings_read_build_info(line))) {
+                report_status_message(STATUS_SETTING_READ_FAIL);
+              } else {
+                report_build_info(line);
+              }
+            } else { // Store startup line
+              if(line[char_counter++] != '=') { return(STATUS_UNSUPPORTED_STATEMENT); }
+              helper_var = char_counter; // Set helper variable as counter to start of user info line.
+              do {
+                line[char_counter-helper_var] = line[char_counter];
+              } while (line[char_counter++] != 0);
+              settings_store_build_info(line);
+            }
+            break;               
           case 'N' : // Startup lines. 
             if ( line[++char_counter] == 0 ) { // Print startup lines
               for (helper_var=0; helper_var < N_STARTUP_LINE; helper_var++) {

report.c

@@ -125,7 +125,7 @@ void report_feedback_message(uint8_t message_code)
 // Welcome message
 void report_init_message()
 {
-  printPgmString(PSTR("\r\nGrbl " GRBL_VERSION " ("GRBL_VERSION_BUILD ") ['$' for help]\r\n"));
+  printPgmString(PSTR("\r\nGrbl " GRBL_VERSION " ['$' for help]\r\n"));
 }
 
 // Grbl help message
@@ -292,6 +292,16 @@ void report_startup_line(uint8_t n, char *line)
   printPgmString(PSTR("\r\n"));
 }
 
+
+// Prints build info line
+void report_build_info(char *line)
+{
+  printPgmString(PSTR("[" GRBL_VERSION "." GRBL_VERSION_BUILD ":"));
+  printString(line);
+  printPgmString(PSTR("]\r\n"));
+}
+
+
  // Prints real-time data. This function grabs a real-time snapshot of the stepper subprogram 
  // and the actual location of the CNC machine. Users may change the following function to their
  // specific needs, but the desired real-time data report must be as short as possible. This is

report.h

@@ -78,4 +78,7 @@ void report_gcode_modes();
 // Prints startup line
 void report_startup_line(uint8_t n, char *line);
 
+// Prints build info and user info
+void report_build_info(char *line);
+
 #endif

settings.c

@@ -50,6 +50,12 @@ void settings_store_startup_line(uint8_t n, char *line)
   memcpy_to_eeprom_with_checksum(addr,(char*)line, LINE_BUFFER_SIZE);
 }
 
+// Method to store build info into EEPROM
+void settings_store_build_info(char *line)
+{
+  memcpy_to_eeprom_with_checksum(EEPROM_ADDR_BUILD_INFO,(char*)line, LINE_BUFFER_SIZE);
+}
+
 // Method to store coord data parameters into EEPROM
 void settings_write_coord_data(uint8_t coord_select, float *coord_data)
 {  
@@ -120,6 +126,19 @@ uint8_t settings_read_startup_line(uint8_t n, char *line)
   }
 }
 
+// Reads startup line from EEPROM. Updated pointed line string data.
+uint8_t settings_read_build_info(char *line)
+{
+  if (!(memcpy_from_eeprom_with_checksum((char*)line, EEPROM_ADDR_BUILD_INFO, LINE_BUFFER_SIZE))) {
+    // Reset line with default value
+    line[0] = 0;
+    settings_store_build_info(line);
+    return(false);
+  } else {
+    return(true);
+  }
+}
+
 // Read selected coordinate data from EEPROM. Updates pointed coord_data value.
 uint8_t settings_read_coord_data(uint8_t coord_select, float *coord_data)
 {

settings.h

@@ -48,6 +48,7 @@
 #define EEPROM_ADDR_GLOBAL 1
 #define EEPROM_ADDR_PARAMETERS 512
 #define EEPROM_ADDR_STARTUP_BLOCK 768
+#define EEPROM_ADDR_BUILD_INFO 992
 
 // Define EEPROM address indexing for coordinate parameters
 #define N_COORDINATE_SYSTEM 6  // Number of supported work coordinate systems (from index 1)
@@ -93,6 +94,10 @@ void settings_store_startup_line(uint8_t n, char *line);
 // Reads an EEPROM startup line to the protocol line variable
 uint8_t settings_read_startup_line(uint8_t n, char *line);
 
+void settings_store_build_info(char *line);
+
+uint8_t settings_read_build_info(char *line);
+
 // Writes selected coordinate data to EEPROM
 void settings_write_coord_data(uint8_t coord_select, float *coord_data);
 

spindle_control.c

@@ -92,5 +92,3 @@ void spindle_run(int8_t direction, uint16_t rpm)
     current_rpm = rpm;
   }
 }
-
-#endif