Use _delay_us() function in the XPROGTarget.c file to ensure timing requirements are met, rather than a fixed number of NOPs.

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

@@ -152,11 +152,9 @@ void XPROGTarget_EnableTargetPDI(void)
 	DDRD |=  (1 << 5) | (1 << 3);
 	DDRD &= ~(1 << 2);
 	
-	/* Set DATA line high for at least 90ns to disable /RESET functionality (note: too long will enable it again,
-	 * so a fixed number of NOPs are used here */
+	/* Set DATA line high for at least 90ns to disable /RESET functionality */
 	PORTD |= (1 << 3);
-	asm volatile ("NOP"::);
-	asm volatile ("NOP"::);
+	_delay_us(1);
 	
 	/* Set up the synchronous USART for XMEGA communications - 
 	   8 data bits, even parity, 2 stop bits */
@@ -168,11 +166,9 @@ void XPROGTarget_EnableTargetPDI(void)
 	BITBANG_PDIDATA_DDR  |= BITBANG_PDIDATA_MASK;
 	BITBANG_PDICLOCK_DDR |= BITBANG_PDICLOCK_MASK;
 	
-	/* Set DATA line high for at least 90ns to disable /RESET functionality (note: too long will enable it again,
-	 * so a fixed number of NOPs are used here */
+	/* Set DATA line high for at least 90ns to disable /RESET functionality */
 	BITBANG_PDIDATA_PORT |= BITBANG_PDIDATA_MASK;
-	asm volatile ("NOP"::);
-	asm volatile ("NOP"::);
+	_delay_us(1);
 
 	/* Fire timer compare channel A ISR to manage the software USART */
 	OCR1A   = BITS_BETWEEN_USART_CLOCKS;
@@ -193,7 +189,7 @@ void XPROGTarget_EnableTargetTPI(void)
 	/* Set /RESET line low for at least 400ns to enable TPI functionality */
 	AUX_LINE_DDR  |=  AUX_LINE_MASK;
 	AUX_LINE_PORT &= ~AUX_LINE_MASK;
-	_delay_ms(1);
+	_delay_us(1);
 
 #if defined(XPROG_VIA_HARDWARE_USART)
 	/* Set Tx and XCK as outputs, Rx as input */