diff --git a/ChangeLog b/ChangeLog
index 3909402..145f0f9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,8 @@
 2017-11-17  NIIBE Yutaka  <gniibe@fsij.org>
 
+	* src/neug.c (crc32_rv_stop): New.
+	(neug_fini): Call crc32_rv_stop.
+
 	* src/main.c (main): Call chopstx_conf_idle.
 
 	* src/usb-ccid.c (usb_event_handle): Use 2 for call of
diff --git a/src/neug.c b/src/neug.c
index 805911c..f630d2a 100644
--- a/src/neug.c
+++ b/src/neug.c
@@ -30,6 +30,7 @@
 #include "sys.h"
 #include "neug.h"
 #ifndef GNU_LINUX_EMULATION
+#include "mcu/stm32.h"
 #include "mcu/stm32f103.h"
 #endif
 #include "adc.h"
@@ -143,6 +144,12 @@ rbit (uint32_t v)
   asm ("rbit	%0, %1" : "=r" (r) : "r" (v));
   return r;
 }
+
+void
+crc32_rv_stop (void)
+{
+  RCC->AHBENR &= ~RCC_AHBENR_CRCEN;
+}
 #endif
 
 static chopstx_mutex_t mode_mtx;
@@ -894,6 +901,7 @@ neug_fini (void)
   rng_should_terminate = 1;
   neug_get (1);
   chopstx_join (rng_thread, NULL);
+  crc32_rv_stop ();
 }
 
 void