diff --git a/sdlogger.py b/sdlogger.py
index 22a0e70..12b30f7 100755
--- a/sdlogger.py
+++ b/sdlogger.py
@@ -8,10 +8,12 @@ BUFFER = bytearray(BUFSIZE_BUFFER)
 
 import os, vfs
 import time
+import json
 
 from machine import UART
 from machine import SPI
 from machine import Pin
+from machine import RTC
 from sdcard import SDCard
 
 BUF_POS = 0
@@ -19,6 +21,9 @@ SD_MOUNT = '/sd'
 LOG_FOLDER = 'logs'
 LOG_FILENAME = 'logfile.log'
 LOG_PATH = SD_MOUNT + '/' + LOG_FOLDER + '/' + LOG_FILENAME
+CMD_PREFIX = const(b"sdlogger {")
+BUF_LASTLINE = bytearray(1024)
+BUF_POS_LASTLINE = 0
 WRITETIME = time.ticks_ms()
 
 UART0 = UART(0, baudrate=115200, rx=20, tx=21, rxbuf=BUFSIZE_RXBUF)
@@ -85,6 +90,84 @@ def readuart():
         tmp = str.encode("\r\nsdlogger: buffer was full\r\n")
         mv[BUF_POS:BUF_POS+len(tmp)] = tmp
 
+def parse_cmd():
+    # find first \n
+    # expand BUF_LASTLINE
+    # check for CMD_PREFIX
+    # 
+    # find last newline
+    # search for CMD_PREFIX between first and last newline
+    #
+    # lastline = from last newline
+    global BUF_POS
+    global BUF_POS_LASTLINE
+    global BUF_LASTLINE
+    global BUFFER
+
+    firstnl = BUFFER.find(b'\r', 0, BUF_POS)
+    if (firstnl != -1) and ((firstnl + BUF_POS_LASTLINE) < len(BUF_LASTLINE)):
+        buf_line_len = BUF_POS_LASTLINE + firstnl
+        BUF_LASTLINE[BUF_POS_LASTLINE:buf_line_len] = BUFFER[0:firstnl]
+        cmd = BUF_LASTLINE.find(CMD_PREFIX, 0, buf_line_len)
+        if (cmd != -1):
+            json_start = cmd + len(CMD_PREFIX) - 1
+            mv = memoryview(BUF_LASTLINE)
+            exec_cmd(mv[json_start:buf_line_len])
+
+    lastnl = BUFFER.rfind(b'\r', BUF_POS)
+    t = BUF_POS - lastnl
+    BUF_LASTLINE[0:t] = BUFFER[lastnl:BUF_POS]
+    cmd  = 0
+    while cmd != -1:
+        cmd = BUFFER.find(CMD_PREFIX, firstnl, lastnl)
+        if cmd != -1:
+            line_end = BUFFER.find(b'\r', cmd, lastnl)
+            json_start = cmd + len(CMD_PREFIX) - 1
+            mv = memoryview(BUFFER)
+            exec_cmd(mv[json_start:line_end])
+
+
+def exec_cmd(json_cmd):
+    try:
+        cmd  = json.loads(json_cmd)
+    except:
+        return
+    if cmd['cmd'] == "rtc":
+        exec_rtc(cmd)
+    elif cmd['cmd'] == "upload":
+        exec_upload(cmd)
+    elif cmd['cmd'] == "reset":
+        exec_reset(cmd)
+
+def exec_rtc(cmd):
+    rtc  = machine.RTC()
+    # the command should have an option "epoch", giving seconds since year 2000
+    rtc.datetime(time.gmtime(cmd['epoch']))
+
+def exec_reset(cmd):
+    import machine
+    machine.reset()
+
+def exec_upload(cmd):
+    # options:
+    # wlan_ssid
+    # wlan_password - optional
+    # upload_server
+    global BUFFER
+    del BUFFER # delete buffer to free some memory for upload process
+    if 'wlan_password' in cmd:
+        pass 
+    else:
+        cmd['wlan_password'] = None
+    import network
+    wlan = network.WLAN(network.WLAN.IF_STA)
+    wlan.active(True)
+    if not wlan.isconnected():
+        wlan.connect(cmd['wlan_ssid'], cmd['wlan_password'])
+        while not wlan.isconnected():
+            pass
+    # TODO: upload file to server
+
 
 def control():
     """main control loop"""
@@ -93,6 +176,7 @@ def control():
         readuart()
     if (BUF_POS > BUF_THRESHOLD) or (BUF_POS > 0 and (1000 < time.ticks_diff(time.ticks_ms(), WRITETIME))):
         # write log if no UART transfer for more than WRITETIME seconds or buffer is fuller than BUF_THRESHOLD
+        parse_cmd()
         writebuf()
 
 def main():