Parse VS and VN HPGL commands

stm32f103t8u6/build_number.txt

@@ -1 +1 @@
-358
+363

stm32f103t8u6/src/hpgl.c

@@ -22,6 +22,9 @@ typedef enum
     HPGL_Parser_ReceivingX,
     HPGL_Parser_ReceivingY,
 
+    // Receiving velocity value
+    HPGL_Parser_ReceivingVelocity,
+
     HPGL_Parser_Error,
 } HPGL_ParserState_t;
 
@@ -45,6 +48,8 @@ void HPGL_Poll(void)
 
     static bool waiting_for_movement_queue = false;
 
+    static unsigned char current_velocity = OUTPUT_DEFAULT_VELOCITY;
+
     if(waiting_for_movement_queue)
     {
         if(!HPGL_EnqueueMovement(waiting_movement))
@@ -100,6 +105,7 @@ void HPGL_Poll(void)
                     // Initialise
                     HPGL_ParseErrorCounter = 0;
                     // No parameters expected for this one
+                    current_velocity = OUTPUT_DEFAULT_VELOCITY;
                     state = HPGL_Parser_Idle;
                     break;
 
@@ -111,6 +117,7 @@ void HPGL_Poll(void)
                 case INST('P', 'U'):
                     // Movement with pen up
                     current_movement.pen_down = false;
+                    current_movement.velocity = current_velocity;
                     current_movement.x = 0;
                     current_movement.y = 0;
                     state = HPGL_Parser_ReceivingX;
@@ -119,11 +126,24 @@ void HPGL_Poll(void)
                 case INST('P', 'D'):
                     // Movement with pen down
                     current_movement.pen_down = true;
+                    current_movement.velocity = current_velocity;
                     current_movement.x = 0;
                     current_movement.y = 0;
                     state = HPGL_Parser_ReceivingX;
                     break;
 
+                case INST('V', 'N'):
+                    // Reset velocity to default
+                    current_velocity = OUTPUT_DEFAULT_VELOCITY;
+                    state = HPGL_Parser_Idle;
+                    break;
+
+                case INST('V', 'S'):
+                    // Velocity set
+                    current_velocity = 0;
+                    state = HPGL_Parser_ReceivingVelocity;
+                    break;
+
                 default:
                     // Unsupported instruction
                     HPGL_ParseErrorCounter++;
@@ -213,6 +233,25 @@ void HPGL_Poll(void)
             }
             break;
 
+        case HPGL_Parser_ReceivingVelocity:
+            if(character == ';' || character == '\n')
+            {
+                // Command finished
+                state = HPGL_Parser_Idle;
+            }
+            else if(character >= '0' && character <= '9')
+            {
+                unsigned int digit = character - '0';
+                current_velocity = current_velocity * 10 + digit;
+            }
+            else
+            {
+                // The VS command could come with a pen number after a comma.
+                // This is currently unsupported.
+                state = HPGL_Parser_Error;
+            }
+            break;
+
         case HPGL_Parser_Error:
             // Exit error state only after end of command
             if(character == '\n' || character == ';')

stm32f103t8u6/src/hpgl.h

@@ -5,6 +5,7 @@
 typedef struct
 {
     bool pen_down;
+    unsigned char velocity;
     unsigned int x;
     unsigned int y;
 } HPGL_Movement_t;

stm32f103t8u6/src/pwm_output.c

@@ -30,7 +30,7 @@ static Output_Coordinate_t Output_CurrentLineStart = {0, 0};
 static Output_Coordinate_t Output_CurrentLineEnd = {0, 0};
 static unsigned int Output_CurrentLineLength;
 static unsigned int Output_CurrentLinePosition;
-static unsigned int Output_CurrentVelocity = OUTPUT_LENGTH_SCALE / 3;
+static unsigned int Output_CurrentVelocity = OUTPUT_DEFAULT_VELOCITY;
 
 bool Output_EnqueueMovement(HPGL_Movement_t movement)
 {
@@ -52,6 +52,10 @@ bool Output_EnqueueMovement(HPGL_Movement_t movement)
     {
         movement.y = OUTPUT_COORDINATE_LIMIT;
     }
+    if(movement.velocity > OUTPUT_MAXIMUM_VELOCITY)
+    {
+        movement.velocity = OUTPUT_MAXIMUM_VELOCITY;
+    }
 
     memcpy(Output_BufferWrite, &movement, sizeof(HPGL_Movement_t));
     Output_BufferWrite++;
@@ -128,6 +132,7 @@ static bool Output_FetchNextPoint(void)
         Output_CurrentLineEnd.x - Output_CurrentLineStart.x,
         Output_CurrentLineEnd.y - Output_CurrentLineStart.y);
     Output_CurrentLinePosition = 0;
+    Output_CurrentVelocity = movement->velocity;
 
     Output_BufferRead++;
     if(Output_BufferRead >= Output_Buffer + CONFIG_BUFFER_MOVEMENTS)

stm32f103t8u6/src/pwm_output.h

@@ -17,6 +17,11 @@
 // overflows during coordinate calculations.
 #define OUTPUT_LENGTH_SCALE     (1 << 3)
 
+// If no velocity is sett via a ‘VS’ command or ‘VN’ is invoked, use this
+// velocity setting
+#define OUTPUT_DEFAULT_VELOCITY (OUTPUT_LENGTH_SCALE / 3)
+#define OUTPUT_MAXIMUM_VELOCITY (OUTPUT_LENGTH_SCALE)  // TODO: Check value
+
 // Delay after initiating pen-up/-down before continuing movements
 #define OUTPUT_PEN_UP_DELAY     200 // In movement timer ticks
 #define OUTPUT_PEN_DOWN_DELAY   20  // In movement timer ticks