Corrected serial mmio

1 files changed, 1 insertions, 1 deletions

diff --git a/cpu/cpu.ml b/cpu/cpu.ml
index e47c0c8..23c0875 100644
--- a/cpu/cpu.ml
+++ b/cpu/cpu.ml
@@ -54,7 +54,7 @@ let cpu_ram ra we wa d =
     let ser_busy = nonnull 8 ser in
     let read_data =
         set_ser_in_busy ser_busy ^.
-        set_next_ser ser ^.
+        set_next_ser (mux read_ser ser (zeroes 8)) ^.
         mux read_ser read_data ser in
 
     set_dbg_ra ra ^.