From d2595129c5c473bcc5c68250007ae58311ad5b8c Mon Sep 17 00:00:00 2001
From: Nico <NicoHood@users.noreply.github.com>
Date: Mon, 2 Feb 2015 20:27:17 +0100
Subject: [PATCH] RX and TX Serial buffer sizes can now be defined
 independently

Fixes #2597
---
 hardware/arduino/avr/cores/arduino/HardwareSerial.h | 9 +++++++--
 hardware/arduino/avr/cores/arduino/USBAPI.h         | 5 +++++
 2 files changed, 12 insertions(+), 2 deletions(-)

diff --git a/hardware/arduino/avr/cores/arduino/HardwareSerial.h b/hardware/arduino/avr/cores/arduino/HardwareSerial.h
index 7dc2aa98c..7f4f162d6 100644
--- a/hardware/arduino/avr/cores/arduino/HardwareSerial.h
+++ b/hardware/arduino/avr/cores/arduino/HardwareSerial.h
@@ -34,12 +34,17 @@
 // location from which to read.
 // NOTE: a "power of 2" buffer size is reccomended to dramatically
 //       optimize all the modulo operations for ring buffers.
-#if !(defined(SERIAL_TX_BUFFER_SIZE) && defined(SERIAL_RX_BUFFER_SIZE))
+#if !defined(SERIAL_TX_BUFFER_SIZE)
 #if (RAMEND < 1000)
 #define SERIAL_TX_BUFFER_SIZE 16
-#define SERIAL_RX_BUFFER_SIZE 16
 #else
 #define SERIAL_TX_BUFFER_SIZE 64
+#endif
+#endif
+#if !defined(SERIAL_RX_BUFFER_SIZE)
+#if (RAMEND < 1000)
+#define SERIAL_RX_BUFFER_SIZE 16
+#else
 #define SERIAL_RX_BUFFER_SIZE 64
 #endif
 #endif
diff --git a/hardware/arduino/avr/cores/arduino/USBAPI.h b/hardware/arduino/avr/cores/arduino/USBAPI.h
index 2fab957f9..5837b3e11 100644
--- a/hardware/arduino/avr/cores/arduino/USBAPI.h
+++ b/hardware/arduino/avr/cores/arduino/USBAPI.h
@@ -59,11 +59,16 @@ extern USBDevice_ USBDevice;
 
 struct ring_buffer;
 
+#ifndef SERIAL_BUFFER_SIZE
 #if (RAMEND < 1000)
 #define SERIAL_BUFFER_SIZE 16
 #else
 #define SERIAL_BUFFER_SIZE 64
 #endif
+#endif
+#if (SERIAL_BUFFER_SIZE>256)
+#error Please lower the CDC Buffer size
+#endif
 
 class Serial_ : public Stream
 {