Set date and time(UTC) from string to RTC chip

README.md

@@ -26,6 +26,10 @@ Simple Python module to deal with DS1302 RTC on Raspberry Pi
 
     ds1302_set_utc
 
+### Set date and time(UTC) from string to RTC chip
+
+    ds1302_set_utc_from_string "09/19/18 13:55:26"
+
 ### Update Rpi system time from RTC chip
 
 Typically call at RPi startup
@@ -39,4 +43,4 @@ Since RTC store only second and not millisecond a 1s delta can occur (or more af
     # drift in second
     echo $(($(date -u -d`ds1302_get_utc` +%s) - $(date -u +%s)))
     # human readable
-    echo "RTC `ds1302_get_utc`"; echo "SYS `date --utc +%FT%TZ`";
+    echo "RTC `ds1302_get_utc`"; echo "SYS `date --utc +%FT%TZ`";

scripts/ds1302_set_utc_from_string

@@ -0,0 +1,28 @@
+#!/usr/bin/env python3
+
+# read date and time from RTC chip, return ISO 8601 UTC string
+# assume DS1302 contain UTC time and not local
+
+import sys
+import pyRPiRTC
+import sys
+from datetime import datetime
+
+rtc = pyRPiRTC.DS1302(clk_pin=11, data_pin=13, ce_pin=15)
+try:
+    # write date and time from system to RTC chip (in UTC) 
+    if len(sys.argv)< 2:
+        exit("use: ds1302_set_utc_from_string '09/19/18 13:55:26' ")
+    dt_write = datetime.strptime(sys.argv[1], '%m/%d/%y %H:%M:%S')
+    # update rtc
+    rtc.write_datetime(dt_write)
+    # check update is good
+    dt_read = rtc.read_datetime()
+    if -2 < (dt_write - dt_read).total_seconds() < +2:
+        print(dt_write.strftime('%Y-%m-%dT%H:%M:%SZ'))
+    else:
+        exit('unable to set RTC time')
+except ValueError:
+    sys.exit('error with RTC chip, check wiring')
+finally:
+    rtc.close()

setup.py

@@ -11,6 +11,7 @@
     ],
     scripts=[
         'scripts/ds1302_get_utc',
-        'scripts/ds1302_set_utc'
+        'scripts/ds1302_set_utc',
+	'scripts/ds1302_set_utc_from_string'
     ]
 )