From 8a0638831fdb69013e0fcd660d2a0897371c8224 Mon Sep 17 00:00:00 2001
From: Sandeep Mistry <s.mistry@arduino.cc>
Date: Fri, 6 Nov 2015 10:34:58 -0500
Subject: [PATCH 1/4] Use EPX_SIZE constant

---
 cores/arduino/USB/USBCore.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/cores/arduino/USB/USBCore.cpp b/cores/arduino/USB/USBCore.cpp
index 9642c2aad..2dedfae19 100644
--- a/cores/arduino/USB/USBCore.cpp
+++ b/cores/arduino/USB/USBCore.cpp
@@ -623,8 +623,8 @@ uint32_t USBDeviceClass::send(uint32_t ep, const void *data, uint32_t len)
 	// Flash area
 	while (len != 0)
 	{
-		if (len >= 64) {
-			length = 64;
+		if (len > EPX_SIZE) {
+			length = EPX_SIZE;
 		} else {
 			length = len;
 		}

From 53ae1b96bfa3efdf41354b3cfffad93be43d0247 Mon Sep 17 00:00:00 2001
From: Sandeep Mistry <s.mistry@arduino.cc>
Date: Fri, 6 Nov 2015 10:36:11 -0500
Subject: [PATCH 2/4] Make whitespace consistent

---
 cores/arduino/USB/USBCore.cpp | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/cores/arduino/USB/USBCore.cpp b/cores/arduino/USB/USBCore.cpp
index 2dedfae19..bb904f84f 100644
--- a/cores/arduino/USB/USBCore.cpp
+++ b/cores/arduino/USB/USBCore.cpp
@@ -679,12 +679,12 @@ uint32_t USBDeviceClass::sendControl(const void* _data, uint32_t len)
 		return length;
 	}
 
- 	while (len > 0)
- 	{
+	while (len > 0)
+	{
 		sent = armSend(EP0, data + pos, len);
 		pos += sent;
 		len -= sent;
- 	}
+	}
 
 	return length;
 }

From 48e5dbb04ef8c1ca26e74da2094ba47ff29afd33 Mon Sep 17 00:00:00 2001
From: Sandeep Mistry <s.mistry@arduino.cc>
Date: Fri, 6 Nov 2015 10:41:21 -0500
Subject: [PATCH 3/4] Send empty transfer if send data length is a multiple of
 EPX_SIZE

This indicates end of transfer
---
 cores/arduino/USB/USBCore.cpp | 11 ++++++++++-
 1 file changed, 10 insertions(+), 1 deletion(-)

diff --git a/cores/arduino/USB/USBCore.cpp b/cores/arduino/USB/USBCore.cpp
index bb904f84f..6948fe1cf 100644
--- a/cores/arduino/USB/USBCore.cpp
+++ b/cores/arduino/USB/USBCore.cpp
@@ -581,6 +581,9 @@ uint8_t USBDeviceClass::armRecv(uint32_t ep)
 uint32_t USBDeviceClass::send(uint32_t ep, const void *data, uint32_t len)
 {
 	uint32_t length = 0;
+	// if len is a multiple of EPX_SIZE an empty transfer needs to be sent
+	// to indicate end of transfer
+	bool sendEmpty = (len % EPX_SIZE) == 0;
 
 	if (!_usbConfiguration)
 		return -1;
@@ -621,7 +624,7 @@ uint32_t USBDeviceClass::send(uint32_t ep, const void *data, uint32_t len)
 #endif
 
 	// Flash area
-	while (len != 0)
+	while (len != 0 || sendEmpty)
 	{
 		if (len > EPX_SIZE) {
 			length = EPX_SIZE;
@@ -645,6 +648,12 @@ uint32_t USBDeviceClass::send(uint32_t ep, const void *data, uint32_t len)
 		while (!usbd.epBank1IsTransferComplete(ep)) {
 			;  // need fire exit.
 		}
+
+		if (len == 0 && sendEmpty) {
+			// empty transfer sent
+			sendEmpty = false;
+		}
+
 		len -= length;
 		data += length;
 	}

From c0b2c7a400a477c974ad19c70f6d19fe211ce32f Mon Sep 17 00:00:00 2001
From: Sandeep Mistry <s.mistry@arduino.cc>
Date: Fri, 13 Nov 2015 09:16:59 -0500
Subject: [PATCH 4/4] Rename sendEmpty to sendZlp

---
 cores/arduino/USB/USBCore.cpp | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/cores/arduino/USB/USBCore.cpp b/cores/arduino/USB/USBCore.cpp
index 6948fe1cf..0c7ef251c 100644
--- a/cores/arduino/USB/USBCore.cpp
+++ b/cores/arduino/USB/USBCore.cpp
@@ -581,9 +581,9 @@ uint8_t USBDeviceClass::armRecv(uint32_t ep)
 uint32_t USBDeviceClass::send(uint32_t ep, const void *data, uint32_t len)
 {
 	uint32_t length = 0;
-	// if len is a multiple of EPX_SIZE an empty transfer needs to be sent
+	// if len is a multiple of EPX_SIZE an ZLP needs to be sent
 	// to indicate end of transfer
-	bool sendEmpty = (len % EPX_SIZE) == 0;
+	bool sendZlp = (len % EPX_SIZE) == 0;
 
 	if (!_usbConfiguration)
 		return -1;
@@ -624,7 +624,7 @@ uint32_t USBDeviceClass::send(uint32_t ep, const void *data, uint32_t len)
 #endif
 
 	// Flash area
-	while (len != 0 || sendEmpty)
+	while (len != 0 || sendZlp)
 	{
 		if (len > EPX_SIZE) {
 			length = EPX_SIZE;
@@ -649,9 +649,9 @@ uint32_t USBDeviceClass::send(uint32_t ep, const void *data, uint32_t len)
 			;  // need fire exit.
 		}
 
-		if (len == 0 && sendEmpty) {
+		if (len == 0 && sendZlp) {
 			// empty transfer sent
-			sendEmpty = false;
+			sendZlp = false;
 		}
 
 		len -= length;