diff --git a/AUTHORS b/AUTHORS
index 9aceb6b..c347954 100644
--- a/AUTHORS
+++ b/AUTHORS
@@ -48,6 +48,7 @@ NIIBE Yutaka:
 
     Under contract of g10 Code GmbH, wrote:
         mcu/usb-usbip.c
+	contrib/usart-stm32f103.c
 
 Paul Fertser:
     Added Blue Pill support.
diff --git a/ChangeLog b/ChangeLog
index f0087f9..7e4365c 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+2017-12-19  NIIBE Yutaka  <gniibe@fsij.org>
+
+	* VERSION: 1.7.
+	* doc/chopstx.texi (VERSION): 1.7.
+
 2017-12-18  NIIBE Yutaka  <gniibe@fsij.org>
 
 	* contrib/usart-stm32f103.c: New.
@@ -14,7 +19,7 @@
 
 	* mcu/sys-stm32f103.h (BOARD_ID_FST_01G): New.
 
-	* contrib/adc-stm32f103.c (get_adc_config): Add case for
+	* contrib/adc-stm32f103.c (get_adc_config): Add a case for
 	BOARD_ID_FST_01G and BOARD_ID_ST_NUCLEO_F103.
 
 2017-11-24  NIIBE Yutaka  <gniibe@fsij.org>
diff --git a/NEWS b/NEWS
index fc95231..a8ac9c0 100644
--- a/NEWS
+++ b/NEWS
@@ -3,12 +3,12 @@ NEWS - Noteworthy changes
 
 * Major changes in Chopstx 1.7
 
-  Released 2017-12-XX
+  Released 2017-12-19
 
 ** Fix: timer wakeup
 Timer expiration had a bug.  When it is waken up, the wake up doesn't
-handle as timer expiration when there are multiple threads on same
-wake up timing.
+handle as a timer expiration when there are multiple threads on same
+timing of expire.  It confuses as if it were forced wakeup.
 
 ** New driver: USART for STM32.
 USART driver for STM32 is added.
diff --git a/README b/README
index b864f05..a947a11 100644
--- a/README
+++ b/README
@@ -1,6 +1,6 @@
 Chopstx - Threads and only Threads
 							 Version 1.7
-							  2017-12-XX
+							  2017-12-19
 							Niibe Yutaka
 					     Flying Stone Technology
 
@@ -17,6 +17,11 @@ stacks, Chopstx just offers a simple RT thread library.
 With Chopstx, interrupt handling is also done by a thread.  This
 enables coherent code for ease of maintenance.
 
+While threads are important, we don't need more threads than
+necessary.  Chopstx provides a feature of poll, so that we can
+minimize use of threads.
+
+
 Note that this library is _not_ related to the hand game:
 
     https://en.wikipedia.org/wiki/Chopsticks_(hand_game)
diff --git a/VERSION b/VERSION
index eaec816..6c0174d 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-release/1.6
+release/1.7
diff --git a/chopstx-cortex-m.c b/chopstx-cortex-m.c
index 28f1d3c..8293cde 100644
--- a/chopstx-cortex-m.c
+++ b/chopstx-cortex-m.c
@@ -287,7 +287,7 @@ chx_request_preemption (uint16_t prio)
  *
  * Returns:
  *          1 on wakeup by others.
- *          0 on normal wakeup (timer expiration, getting lock).
+ *          0 on normal wakeup (timer expiration, lock aquirement).
  *         -1 on cancellation.
  */
 static uintptr_t __attribute__ ((naked, noinline))
diff --git a/contrib/usart-stm32f103.c b/contrib/usart-stm32f103.c
index 2d234d6..2551260 100644
--- a/contrib/usart-stm32f103.c
+++ b/contrib/usart-stm32f103.c
@@ -617,7 +617,7 @@ usart_send_break (uint8_t dev_no)
     return -1;
 
   if ((USARTx->CR1 & 0x01))
-    return 1;			/* Busy sending break, which was requested before.  */
+    return 1;	/* Busy sending break, which was requested before.  */
 
   USARTx->CR1 |= 0x01;
   return 0;
diff --git a/doc/chopstx.texi b/doc/chopstx.texi
index 7e6994e..526ae6a 100644
--- a/doc/chopstx.texi
+++ b/doc/chopstx.texi
@@ -1,7 +1,7 @@
 \input texinfo                      @c -*-texinfo-*-
 @c %**start of header
 @setfilename chopstx.info
-@set VERSION 1.6
+@set VERSION 1.7
 @settitle Chopstx Reference Manual
 @c Unify some of the indices.
 @syncodeindex tp fn
@@ -60,7 +60,8 @@ section entitled ``Copying''.
 @menu
 * Introduction::                 What is Chopstx.
 * Threads and only Threads::     Threads and only Threads.
-* Note: Use of sleep mode::      Use it carefully.
+* Poll or Pole::                 Poll or Pole.
+* Note (Use of sleep mode)::     Use it carefully.
 * API::                          API.
 
 Appendix
@@ -90,11 +91,16 @@ Cortex-M3 and GNU/Linux emulation.  Specifically, it is used for
 STM32F030, MKL27Z, STM32F103 and as a command on GNU/Linux.
 
 While most RTOSes come with many features, drivers, and stacks,
-Chopstx just offers a RT thread library.
+Chopstx just offers an RT thread library.
 
 With Chopstx, interrupt handling is also done by a thread.  This
 enables coherent code for ease of maintenance.
 
+While threads are important, we don't need more threads than
+necessary.  Chopstx provides a feature of poll, so that we can
+minimize use of threads.
+
+
 @node Threads and only Threads
 @chapter Threads and only Threads
 
@@ -129,8 +135,17 @@ support more performance (frequency).  In general, such an example is
 best suited by hardware (not software).
 
 
-@node Note: Use of sleep mode
-@chapter Note: Use of sleep mode
+@node Poll or Pole
+@chapter Poll or Pole
+Chopstx provides the @code{chopstx_poll} function to wait on multiple events.
+
+Using @code{chopstx_poll}, we can write an application by event-driven
+programming style, with minimum number of threads, avoiding
+complicated dependency between threads.
+
+
+@node Note (Use of sleep mode)
+@chapter Note (Use of sleep mode)
 
 Calling the chopstx_conf_idle function (> 0) to allow the idle thread
 going to sleep.  MCU will be in sleep mode when no threads are