Some error handling.

+ TUSBPacketBuffer type

source/usbasp.pas

@@ -115,7 +115,7 @@ type
     FStatus_RxEvent, FStatus_TxEvent, FUART_RxEvent, FUART_TxEvent,
     FUnpluggedEvent: TEvent;
 
-    //FLastUsbError: integer;
+    FHidErrorStr: string;
 
     FUART_RxBuffer, FUART_TxBuffer, FStatus_RxBuffer,
     FStatus_TxBuffer: TSPSCRingBuffer;
@@ -151,6 +151,9 @@ type
 
 implementation
 
+type
+  TUSBPacketBuffer = array[0..8] of byte;
+
 { TUSBasp }
 
 constructor TUSBasp.Create;
@@ -176,8 +179,7 @@ begin
   FUnpluggedEvent := TEvent.Create(nil, False, False, 'UNPLD_' +
     IntToStr(Random(999)));
 
-  if HidInit = 0 then
-    HIDEnumerate;
+  HidInit();
 
 end;
 
@@ -207,7 +209,15 @@ begin
   if not FConnected then
   begin
 
+    if not HIDEnumerate(ASerialNumber) then
+      Exit;
+
     FUART_HIDDevice := THidDevice.OpenPath(FUART_HIDDevicePath);
+    FHidErrorStr := FUART_HIDDevice^.GetError;
+
+    if FHidErrorStr <> 'Success' then
+      Exit;
+
     FUART_HIDDevice^.SetNonBlocking(0);
 
     FUART_RxThread := TThread_HID_UART_Rx.Create(
@@ -218,12 +228,18 @@ begin
     if FHasStatus then
     begin
       FStatus_HIDDevice := THidDevice.OpenPath(FStatus_HIDDevicePath);
-      FStatus_HIDDevice^.SetNonBlocking(0);
+      FHidErrorStr := FStatus_HIDDevice^.GetError;
+
+      if FHidErrorStr = 'Success' then
+      begin
+        FStatus_HIDDevice^.SetNonBlocking(0);
 
-      FStatus_RxThread := TThread_HID_Status_Rx.Create(FStatus_HIDDevice,
-        FStatus_RxBuffer, FStatus_RxEvent, FUnpluggedEvent);
-      FStatus_TxThread := TThread_HID_Status_Tx.Create(FStatus_HIDDevice,
-        FStatus_TxBuffer, FStatus_TxEvent, FUnpluggedEvent);
+        FStatus_RxThread := TThread_HID_Status_Rx.Create(FStatus_HIDDevice,
+          FStatus_RxBuffer, FStatus_RxEvent, FUnpluggedEvent);
+
+        FStatus_TxThread := TThread_HID_Status_Tx.Create(FStatus_HIDDevice,
+          FStatus_TxBuffer, FStatus_TxEvent, FUnpluggedEvent);
+      end;
     end;
 
     FConnected := True;
@@ -273,7 +289,7 @@ end;
 function TUSBasp.UARTOpen(const ABaudRate, ADataBits, AParity,
   AStopBits: integer): boolean;
 var
-  Buffer: array[0..8] of byte = (0, 0, 0, 0, 0, 0, 0, 0, 0);
+  Buffer: TUSBPacketBuffer;
   Prescaler: word;
 begin
   if FConnected and not FUARTOpened then
@@ -294,7 +310,7 @@ end;
 
 function TUSBasp.UARTClose: boolean;
 var
-  Buffer: array[0..8] of byte = (0, 0, 0, 0, 0, 0, 0, 0, 0);
+  Buffer: TUSBPacketBuffer;
 begin
   if FConnected and FUARTOpened then
   begin
@@ -316,7 +332,7 @@ function TUSBasp.HIDEnumerate(const ASerialNumber: string): boolean;
 var
   HidItemRoot, HidItem: PHidDeviceInfo;
   HIDDeviceMatch: boolean;
-  FeatureReportBuffer: array[0..8] of byte = (0, 0, 0, 0, 0, 0, 0, 0, 0);
+  FeatureReportBuffer: TUSBPacketBuffer;
 begin
   Result := False;
 
@@ -347,7 +363,6 @@ begin
           2: begin
             FStatus_HIDDevicePath := HidItem^.Path;
             FHasStatus := True;
-            Break;
           end;
         end;
 
@@ -391,7 +406,7 @@ end;
 
 function TUSBasp.ChangeSerialNumber(const ASerialNumber: string): integer;
 var
-  Buffer: array[0..8] of byte = (0, 0, 0, 0, 0, 0, 0, 0, 0);
+  Buffer: TUSBPacketBuffer;
   ErrorCode: integer;
   SerNumValue: word;
 begin