diff --git a/firmware/src_simtrace/ringbuffer.h b/firmware/src_simtrace/ringbuffer.h
new file mode 100644
index 0000000..691c62b
--- /dev/null
+++ b/firmware/src_simtrace/ringbuffer.h
@@ -0,0 +1,22 @@
+#ifndef SIMTRACE_RINGBUF_H
+#define SIMTRACE_RINGBUF_H
+
+#include <stdint.h>
+#include <stdbool.h>
+#include <sys/types.h>
+
+#define RING_BUFLEN 64
+
+typedef struct ringbuf {
+    uint8_t buf[RING_BUFLEN];
+    size_t ird;
+    size_t iwr;
+} ringbuf;
+
+void rbuf_reset(volatile ringbuf *rb);
+uint8_t rbuf_read(volatile ringbuf *rb);
+void rbuf_write(volatile ringbuf *rb, uint8_t item);
+bool rbuf_is_empty(volatile ringbuf *rb);
+bool rbuf_is_full(volatile ringbuf *rb);
+
+#endif /* end of include guard: SIMTRACE_RINGBUF_H */