diff --git a/soc/runtime/exceptions.c b/soc/runtime/exceptions.c
index 34e0affde..d6c2e9d10 100644
--- a/soc/runtime/exceptions.c
+++ b/soc/runtime/exceptions.c
@@ -14,7 +14,7 @@ static int stored_id;
 void *exception_push(void)
 {
     if(ec_top >= MAX_EXCEPTION_CONTEXTS)
-        exception_raise(EID_NOMEM);
+        exception_raise(EID_OUT_OF_MEMORY);
     return exception_contexts[ec_top++].jb;
 }
 
diff --git a/soc/runtime/exceptions.h b/soc/runtime/exceptions.h
index f5b9782ac..d701153b0 100644
--- a/soc/runtime/exceptions.h
+++ b/soc/runtime/exceptions.h
@@ -2,7 +2,8 @@
 #define __EXCEPTIONS_H
 
 enum {
-	EID_NOMEM = 0
+	EID_OUT_OF_MEMORY = 0,
+	EID_RTIO_UNDERFLOW = 1
 };
 
 int exception_setjmp(void *jb) __attribute__((returns_twice));
diff --git a/soc/runtime/rtio.c b/soc/runtime/rtio.c
index 8ee74dafc..6f38b9419 100644
--- a/soc/runtime/rtio.c
+++ b/soc/runtime/rtio.c
@@ -1,5 +1,6 @@
 #include <generated/csr.h>
 
+#include "exceptions.h"
 #include "rtio.h"
 
 void rtio_init(void)
@@ -21,6 +22,8 @@ void rtio_set(long long int timestamp, int channel, int value)
     rtio_o_value_write(value);
     while(!rtio_o_writable_read());
     rtio_o_we_write(1);
+    if(rtio_o_error_read())
+        exception_raise(EID_RTIO_UNDERFLOW);
 }
 
 void rtio_replace(long long int timestamp, int channel, int value)