diff --git a/sys/include/od.h b/sys/include/od.h
index 8cd2d20159bbb14dea39c23fa4177050dbf20809..d7120659c0b05a4b69be633c92a50a656f585fb3 100644
--- a/sys/include/od.h
+++ b/sys/include/od.h
@@ -136,7 +136,7 @@ extern "C" {
  * @param[in] flags     Flags as defined in @ref od_flags_address and
  *                      @ref od_flags_bytes
  */
-void od(void *data, size_t data_len, uint8_t width, uint16_t flags);
+void od(const void *data, size_t data_len, uint8_t width, uint16_t flags);
 
 /**
  * @brief Dumps memory stored at *data* up to *data_len* in octal, decimal, or
@@ -148,7 +148,7 @@ void od(void *data, size_t data_len, uint8_t width, uint16_t flags);
  * @param[in] width     Number of bytes per line. If *width* is 0,
  *                      @ref OD_WIDTH_DEFAULT is assumed as a default value.
  */
-static inline void od_hex_dump(void *data, size_t data_len, uint8_t width)
+static inline void od_hex_dump(const void *data, size_t data_len, uint8_t width)
 {
     od(data, data_len, width, OD_FLAGS_ADDRESS_HEX | OD_FLAGS_BYTES_HEX | OD_FLAGS_LENGTH_1);
 }
diff --git a/sys/od/od.c b/sys/od/od.c
index 87098c8e4ae9fd8c8ef32900cb9a8f88e8c52355..b49af2996d541b65b130051ef9abd33377911d23 100644
--- a/sys/od/od.c
+++ b/sys/od/od.c
@@ -178,7 +178,7 @@ static inline void _bytes_format(char *format, uint16_t flags)
     }
 }
 
-static void _print_date(void *data, size_t offset, char *format, uint8_t length,
+static void _print_date(const void *data, size_t offset, char *format, uint8_t length,
                         uint16_t flags)
 {
     switch (length) {
@@ -287,7 +287,7 @@ static int _log10(uint8_t a)
     return ++res;
 }
 
-void od(void *data, size_t data_len, uint8_t width, uint16_t flags)
+void od(const void *data, size_t data_len, uint8_t width, uint16_t flags)
 {
     char address_format[5];
     uint8_t date_length = _length(flags);