adding to lisp library

LispLibrary.h

@@ -172,5 +172,31 @@ Returns a list with all items for which tst is true removed from lst."
 Returns a list with all items for which tst is false removed from lst."
   (mapcan #'(lambda (x) (when (funcall tst x) (list x))) lst))
 
+(defun rtc-set (hr min)
+ "(rtc-set hr min)
+Set the time on a DS3231 RTC. Times are in BCD, so use
+the appropriate reader macro, e.g. (rtc-set #x12 #x34)
+for 12:34. Assumes seconds are zero."
+  (with-i2c (str #x68)
+    (write-byte 0 str)
+    (write-byte 0 str)
+    (write-byte min str)
+    (write-byte hr str)))
+
+(defun rtc-get ()
+  (with-i2c (str #x68)
+    (write-byte 0 str)
+    (restart-i2c str 3)
+    (reverse
+      (list
+        (read-byte str)
+        (read-byte str)
+        (read-byte str)))))
+
+(defun rtc-now ()
+ "(rtc-now)
+Set the time using the RTC."
+  (now (rtc-get)))
+
 )lisplibrary";