X-Git-Url: http://git.linex4red.de/pub/USBasp.git/blobdiff_plain/d753512ccae76a4fce665b2c16ba7d5867143a96..7ef58eef7a57c46ab53ed8a26805b58dcffd7010:/Demos/Device/ClassDriver/Keyboard/Keyboard.c

diff --git a/Demos/Device/ClassDriver/Keyboard/Keyboard.c b/Demos/Device/ClassDriver/Keyboard/Keyboard.c
index ea373a802..2918f5a67 100644
--- a/Demos/Device/ClassDriver/Keyboard/Keyboard.c
+++ b/Demos/Device/ClassDriver/Keyboard/Keyboard.c
@@ -144,22 +144,34 @@ bool CALLBACK_HID_Device_CreateHIDReport(USB_ClassInfo_HID_Device_t* const HIDIn
 	uint8_t JoyStatus_LCL    = Joystick_GetStatus();
 	uint8_t ButtonStatus_LCL = Buttons_GetStatus();
 
+	static uint8_t PrevUsedKeyCodes;
+	uint8_t UsedKeyCodes = 0;
+	
 	if (JoyStatus_LCL & JOY_UP)
-	  KeyboardReport->KeyCode[0] = 0x04; // A
+	  KeyboardReport->KeyCode[UsedKeyCodes++] = 0x04; // A
 	else if (JoyStatus_LCL & JOY_DOWN)
-	  KeyboardReport->KeyCode[0] = 0x05; // B
+	  KeyboardReport->KeyCode[UsedKeyCodes++] = 0x05; // B
 
 	if (JoyStatus_LCL & JOY_LEFT)
-	  KeyboardReport->KeyCode[0] = 0x06; // C
+	  KeyboardReport->KeyCode[UsedKeyCodes++] = 0x06; // C
 	else if (JoyStatus_LCL & JOY_RIGHT)
-	  KeyboardReport->KeyCode[0] = 0x07; // D
+	  KeyboardReport->KeyCode[UsedKeyCodes++] = 0x07; // D
 
 	if (JoyStatus_LCL & JOY_PRESS)
-	  KeyboardReport->KeyCode[0] = 0x08; // E
+	  KeyboardReport->KeyCode[UsedKeyCodes++] = 0x08; // E
 	  
 	if (ButtonStatus_LCL & BUTTONS_BUTTON1)
-	  KeyboardReport->KeyCode[0] = 0x09; // F
+	  KeyboardReport->KeyCode[UsedKeyCodes++] = 0x09; // F
 	
+	/* The host will ignore the device if we add a new keycode to the report while another keycode is currently
+	 * being sent (i.e. the user has pressed another key while a key is already being pressed) - we need to intersperse
+	 * the two reports with a zeroed report to force the host to accept the additional keys */
+	if (UsedKeyCodes != PrevUsedKeyCodes)
+	{
+		memset(KeyboardReport, sizeof(USB_KeyboardReport_Data_t), 0x00);
+		PrevUsedKeyCodes = UsedKeyCodes;
+	}
+
 	*ReportSize = sizeof(USB_KeyboardReport_Data_t);
 	return false;
 }