diff --git a/circuitpython/main.py b/circuitpython/main.py
index 9ef1e23..a0660f5 100644
--- a/circuitpython/main.py
+++ b/circuitpython/main.py
@@ -24,7 +24,7 @@ Use with:
 
 TODO for v1 :
  * write data on flash drive
- * send data trough UART (new one !)
+ * send data through UART  (one more !)
 """
 __version__ = 0.1
 __repo__ = "https://framagit.org/arofarn/Cameteo"
@@ -33,9 +33,10 @@ __repo__ = "https://framagit.org/arofarn/Cameteo"
 # config #
 ##########
 print_data = True
+backup_data = True
 data_to_neopixel = True
 gps_enable = True
-update_interval = 5   # in seconds
+update_interval = 60   # in seconds
 send_json_data = True
 datetime_format = "{:04}/{:02}/{:02}_{:02}:{:02}:{:02}"
 neopixel_max_value =const(100)    #max value instead of brightness to spare some mem
@@ -78,9 +79,9 @@ class Data:
         #  65536 : 16bit ADC
 
         #Data from BME280
-        self.data['BME280'] = {'temp': { 'val': bme280.temperature, 'unit': '°C' },
-                               'hum': { 'val': bme280.humidity, 'unit': '%' },
-                               'press': { 'val': bme280.pressure, 'unit': 'hPa' }}
+        self.data['BME280'] = {'temp': { 'val': round(bme280.temperature, 1), 'unit': '°C' },
+                               'hum': { 'val': int(bme280.humidity), 'unit': '%' },
+                               'press': { 'val': round(bme280.pressure, 2), 'unit': 'hPa' }}
         if gps_enable:
             if gps.has_fix:
                 self.data['GPS'] = {'timestamp': {'val': datetime_format.format(gps.timestamp_utc.tm_year,
@@ -127,6 +128,18 @@ class Data:
         output = output + "}"
         return output
 
+    def write_on_flash(self):
+        """Save the current data as csv file on SPI flash"""
+        try:
+            with open("data/data.csv", "a") as csv_file:
+                csv_file.write("{};{};{};{}\n".format(self.data['SYS']['time']['val'],
+                                                      self.data['BME280']['temp']['val'],
+                                                      self.data['BME280']['hum']['val'],
+                                                      self.data['BME280']['press']['val']))
+        except OSError as e:
+            print("Err. {} : R-O FS".format(e))
+
+
 #############
 # Functions #
 #############
@@ -244,6 +257,8 @@ while True:
         if print_data:
             data.show()
             # print(data.json())
+        if backup_data:
+            data.write_on_flash()
         if data_to_neopixel:
             pixel[0] = update_neopixel(data.data)
         gc.collect()