diff --git a/include/arch/msp430fr5969lp/driver/stdin.h b/include/arch/msp430fr5969lp/driver/stdin.h
index 108511193c68c93ba2fdedf3385bbf153c8205ee..7b78a9a8fba295ebfaea2ab7b6510a271136b749 100644
--- a/include/arch/msp430fr5969lp/driver/stdin.h
+++ b/include/arch/msp430fr5969lp/driver/stdin.h
@@ -9,8 +9,10 @@
 class StandardInput {
 	private:
 		StandardInput(const StandardInput &copy);
-		char buffer[8];
-		unsigned char write_pos, read_pos;
+		static unsigned char const bufsize = 16;
+		char buffer[bufsize];
+		volatile unsigned char write_pos;
+		unsigned char read_pos;
 
 	public:
 		StandardInput() : write_pos(0), read_pos(0) {}
@@ -20,7 +22,7 @@ class StandardInput {
 
 		inline void addKey(char key) {
 			buffer[write_pos++] = key;
-			write_pos %= 8;
+			write_pos %= bufsize;
 		}
 };
 
diff --git a/include/arch/msp430fr5994lp/driver/stdin.h b/include/arch/msp430fr5994lp/driver/stdin.h
index 108511193c68c93ba2fdedf3385bbf153c8205ee..7b78a9a8fba295ebfaea2ab7b6510a271136b749 100644
--- a/include/arch/msp430fr5994lp/driver/stdin.h
+++ b/include/arch/msp430fr5994lp/driver/stdin.h
@@ -9,8 +9,10 @@
 class StandardInput {
 	private:
 		StandardInput(const StandardInput &copy);
-		char buffer[8];
-		unsigned char write_pos, read_pos;
+		static unsigned char const bufsize = 16;
+		char buffer[bufsize];
+		volatile unsigned char write_pos;
+		unsigned char read_pos;
 
 	public:
 		StandardInput() : write_pos(0), read_pos(0) {}
@@ -20,7 +22,7 @@ class StandardInput {
 
 		inline void addKey(char key) {
 			buffer[write_pos++] = key;
-			write_pos %= 8;
+			write_pos %= bufsize;
 		}
 };
 
diff --git a/src/arch/msp430fr5969lp/driver/stdin.cc b/src/arch/msp430fr5969lp/driver/stdin.cc
index 033349d64121373152f8f23d1f0595b77d3fe461..6ad43b873ffbf95e1411a444db4fb2bbe2a198b4 100644
--- a/src/arch/msp430fr5969lp/driver/stdin.cc
+++ b/src/arch/msp430fr5969lp/driver/stdin.cc
@@ -22,7 +22,7 @@ bool StandardInput::hasKey()
 char StandardInput::getKey()
 {
 	char ret = buffer[read_pos++];
-	read_pos %= 8;
+	read_pos %= bufsize;
 	return ret;
 }
 
diff --git a/src/arch/msp430fr5994lp/driver/stdin.cc b/src/arch/msp430fr5994lp/driver/stdin.cc
index 033349d64121373152f8f23d1f0595b77d3fe461..6ad43b873ffbf95e1411a444db4fb2bbe2a198b4 100644
--- a/src/arch/msp430fr5994lp/driver/stdin.cc
+++ b/src/arch/msp430fr5994lp/driver/stdin.cc
@@ -22,7 +22,7 @@ bool StandardInput::hasKey()
 char StandardInput::getKey()
 {
 	char ret = buffer[read_pos++];
-	read_pos %= 8;
+	read_pos %= bufsize;
 	return ret;
 }