Added reliability patches to the AVRISP-MKII Clone project's PDI/TPI protocols (thanks to Justin Mattair).

LUFA/ManPages/ChangeLog.txt

@@ -24,7 +24,7 @@
   *  - Core:
   *   - None
   *  - Library Applications:
-  *   - None
+  *   - Added reliability patches to the AVRISP-MKII Clone project's PDI/TPI protocols (thanks to Justin Mattair)
   *
   *  \section Sec_ChangeLog111009 Version 111009
   *  <b>New:</b>

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

@@ -149,13 +149,18 @@ void XMEGANVM_DisablePDI(void)
 {
 	XMEGANVM_WaitWhileNVMBusBusy();
 
-	/* Clear the RESET key in the RESET PDI register to allow the XMEGA to run */
-	XPROGTarget_SendByte(PDI_CMD_STCS | PDI_RESET_REG);
-	XPROGTarget_SendByte(0x00);
-
-	/* Do it twice to make sure it takes effect (silicon bug?) */
-	XPROGTarget_SendByte(PDI_CMD_STCS | PDI_RESET_REG);
-	XPROGTarget_SendByte(0x00);
+	/* Clear the RESET key in the RESET PDI register to allow the XMEGA to run - must perform this until the 
+	 * change takes effect, as in some cases it takes multiple writes (silicon bug?).
+	 */
+	do
+	{
+		/* Clear reset register */
+		XPROGTarget_SendByte(PDI_CMD_STCS | PDI_RESET_REG);
+		XPROGTarget_SendByte(0x00);
+	
+		/* Read back the reset register, check to see if it took effect */
+		XPROGTarget_SendByte(PDI_CMD_LDCS | PDI_RESET_REG);
+	} while (XPROGTarget_ReceiveByte() != 0x00);
 
 	XPROGTarget_DisableTargetPDI();
 }

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

@@ -92,7 +92,8 @@ void XPROGTarget_EnableTargetTPI(void)
 void XPROGTarget_DisableTargetPDI(void)
 {
 	/* Switch to Rx mode to ensure that all pending transmissions are complete */
-	XPROGTarget_SetRxMode();
+	if (IsSending)
+	  XPROGTarget_SetRxMode();
 
 	/* Turn off receiver and transmitter of the USART, clear settings */
 	UCSR1A  = ((1 << TXC1) | (1 << RXC1));
@@ -108,7 +109,8 @@ void XPROGTarget_DisableTargetPDI(void)
 void XPROGTarget_DisableTargetTPI(void)
 {
 	/* Switch to Rx mode to ensure that all pending transmissions are complete */
-	XPROGTarget_SetRxMode();
+	if (IsSending)
+	  XPROGTarget_SetRxMode();
 
 	/* Turn off receiver and transmitter of the USART, clear settings */
 	UCSR1A |= (1 << TXC1) | (1 << RXC1);
@@ -169,19 +171,16 @@ void XPROGTarget_SendIdle(void)
 		/* Wait for a full cycle of the clock */
 		while (PIND & (1 << 5));
 		while (!(PIND & (1 << 5)));
+		while (PIND & (1 << 5));
 	}
 }
 
 static void XPROGTarget_SetTxMode(void)
 {
-    /* Need to do nothing for a full frame to send a BREAK - only one cycle should be needed, however
-	 * there are reports that sometimes the interface will get stuck in some environments. */
-    for (uint8_t i = 0; i < BITS_IN_USART_FRAME; i++)
-    {
-        /* Wait for a full cycle of the clock */
-        while (PIND & (1 << 5));
-        while (!(PIND & (1 << 5)));
-    }
+	/* Wait for a full cycle of the clock */
+	while (PIND & (1 << 5));
+	while (!(PIND & (1 << 5)));
+	while (PIND & (1 << 5));
 
 	PORTD  |=  (1 << 3);
 	DDRD   |=  (1 << 3);