Added new XCK_RESCUE_CLOCK_ENABLE compile time option to the AVRISP-MKII clone programmer project (thanks to Tom Light).

LUFA/ManPages/ChangeLog.txt

@@ -35,6 +35,7 @@
   *  - Added new Pipe_GetBusyBanks(), Endpoint_GetBusyBanks() and Endpoint_AbortPendingIN() functions
   *  - Added new NO_BLOCK_SUPPORT, NO_EEPROM_BYTE_SUPPORT, NO_FLASH_BYTE_SUPPORT and NO_LOCK_BYTE_WRITE_SUPPORT compile time options to the
   *    CDC class bootloader
+  *  - Added new XCK_RESCUE_CLOCK_ENABLE compile time option to the AVRISP-MKII clone programmer project (thanks to Tom Light)
   *
   *  <b>Changed:</b>
   *  - Removed complicated logic for the Endpoint_ConfigureEndpoint() function to use inlined or function called versions

Projects/AVRISP-MKII/AVRISP-MKII.txt

@@ -280,6 +280,12 @@
  *    <td>Define to switch to a non-standard endpoint scheme, breaking compatibility with AVRStudio under Windows but making
  *        the code compatible with software such as avrdude (all platforms) that use the libUSB driver.
  *   </tr>
+ *   <tr>
+ *    <td>XCK_RESCUE_CLOCK_ENABLE</td>
+ *    <td>Makefile LUFA_OPTS</td>
+ *    <td>Define to move the ISP rescue clock to the AVR's XCK pin instead of the OCR1A output pin. This is useful for existing programming
+ *        hardware that does not expose the OCR1A pin of the AVR, but *may* cause some issues with PDI programming mode.
+ *   </tr>
  *  </table>
  */
 

Projects/AVRISP-MKII/Lib/ISP/ISPTarget.c

@@ -189,6 +189,15 @@ void ISPTarget_DisableTargetISP(void)
  */
 void ISPTarget_ConfigureRescueClock(void)
 {
+	#if defined(XCK_RESCUE_CLOCK_ENABLE)
+		/* Configure XCK as an output for the specified AVR model */
+		DDRD  |= (1 << 5);
+		
+		/* Start USART to generate a 4MHz clock on the XCK pin */
+		UBRR1  = ((F_CPU / 2 / ISP_RESCUE_CLOCK_SPEED) - 1);
+		UCSR1B = (1 << TXEN1);
+		UCSR1C = (1 << UMSEL10) | (1 << UPM11) | (1 << USBS1) | (1 << UCSZ11) | (1 << UCSZ10) | (1 << UCPOL1);
+	#else
 		/* Configure OCR1A as an output for the specified AVR model */
 		#if defined(USB_SERIES_2_AVR)
 		DDRC |= (1 << 6);
@@ -202,6 +211,7 @@ void ISPTarget_ConfigureRescueClock(void)
 		OCR1A  = ((F_CPU / 2 / ISP_RESCUE_CLOCK_SPEED) - 1);
 		TCCR1A = (1 << COM1A0);
 		TCCR1B = ((1 << WGM12) | (1 << CS10));
+	#endif
 }
 
 /** Configures the AVR's timer ready to produce software ISP for the slower ISP speeds that

Projects/AVRISP-MKII/Lib/XPROG/XPROGProtocol.c

@@ -196,6 +196,10 @@ static void XPROGProtocol_LeaveXPROGMode(void)
 		XPROGTarget_DisableTargetTPI();
 	}
 
+	#if defined(XCK_RESCUE_CLOCK_ENABLE) && defined(ENABLE_ISP_PROTOCOL)
+	ISPTarget_ConfigureRescueClock();
+	#endif
+
 	Endpoint_Write_Byte(CMD_XPROG);
 	Endpoint_Write_Byte(XPRG_CMD_LEAVE_PROGMODE);
 	Endpoint_Write_Byte(XPRG_ERR_OK);

Projects/AVRISP-MKII/makefile

@@ -137,6 +137,7 @@ LUFA_OPTS += -D VTARGET_REF_VOLTS=5
 LUFA_OPTS += -D VTARGET_SCALE_FACTOR=1
 #LUFA_OPTS += -D NO_VTARGET_DETECT
 #LUFA_OPTS += -D LIBUSB_DRIVER_COMPAT
+#LUFA_OPTS += -D XCK_RESCUE_CLOCK_ENABLE
 
 
 # Create the LUFA source path variables by including the LUFA root makefile