diff --git a/lib/stream.c b/lib/stream.c
index 5c0ea6c..8e357ee 100644
--- a/lib/stream.c
+++ b/lib/stream.c
@@ -3,6 +3,7 @@
 #include <stdint.h>
 
 #include "stream.h"
+#include "calc.h"
 
 
 static char tmpstr[20]; // buffer for number rendering
@@ -76,6 +77,54 @@ void put_i32(const STREAM *p, const int32_t num)
 }
 
 
+/** Print number as hex */
+void _print_hex(const STREAM *p, uint8_t* start, uint8_t bytes)
+{
+	for (; bytes > 0; bytes--) {
+		uint8_t b = *(start + bytes - 1);
+
+		for(uint8_t j = 0; j < 2; j++) {
+			uint8_t x = high_nibble(b);
+			b = b << 4;
+			if (x < 0xA) {
+				p->tx('0' + x);
+			} else {
+				p->tx('A' + (x - 0xA));
+			}
+		}
+	}
+}
+
+
+/** Send unsigned int8 */
+void put_x8(const STREAM *p, const uint8_t num)
+{
+	_print_hex(p, (uint8_t*) &num, 1);
+}
+
+
+/** Send int as hex */
+void put_x16(const STREAM *p, const uint16_t num)
+{
+	_print_hex(p, (uint8_t*) &num, 2);
+}
+
+
+/** Send long as hex */
+void put_x32(const STREAM *p, const uint32_t num)
+{
+	_print_hex(p, (uint8_t*) &num, 4);
+}
+
+
+/** Send long long as hex */
+void put_x64(const STREAM *p, const uint64_t num)
+{
+	_print_hex(p, (uint8_t*) &num, 8);
+}
+
+
+
 // float variant doesn't make sense for 8-bit int
 
 /** Send unsigned int as float */
diff --git a/lib/stream.h b/lib/stream.h
index 3d9feb6..5c7ca32 100644
--- a/lib/stream.h
+++ b/lib/stream.h
@@ -1,8 +1,20 @@
 #pragma once
 
 //
-// Stream utilities - printing abstraction
-// Works with eg. UART
+// Streams -- in this library -- are instances of type STREAM.
+//
+// A stream can be used for receiving and sending bytes, generally
+// it's a pipe to a device.
+//
+// They are designed for printing numbers and strings, but can
+// also be used for general data transfer.
+//
+// Examples of streams:
+// "uart.h" -> declares global variable "uart" which is a pointer to the UART stream
+// "lcd.h" -> declares a global variable "lcd" (pointer to LCD scho stream)
+//
+// Streams help avoid code duplication, since the same functions can be used
+// to format and print data to different device types.
 //
 
 #include <stdlib.h>
@@ -49,6 +61,22 @@ void put_u32(const STREAM *p, const uint32_t num);
 void put_i32(const STREAM *p, const int32_t num);
 
 
+/** Send unsigned int8 */
+void put_x8(const STREAM *p, const uint8_t num);
+
+
+/** Send int as hex */
+void put_x16(const STREAM *p, const uint16_t num);
+
+
+/** Send long as hex */
+void put_x32(const STREAM *p, const uint32_t num);
+
+
+/** Send long long as hex */
+void put_x64(const STREAM *p, const uint64_t num);
+
+
 // float variant doesn't make sense for 8-bit int
 
 /** Send unsigned int as float */