Add python helper scripts for example tasks

* Setting time when the WINC1500 can't locate an NTP that responds (most often because of firewall settings)
* Extract the pem formatted public key

Author: bryan-hunt

scripts/at_kit_base.py

@@ -1,5 +1,9 @@
+#!/usr/bin/env python
+
 import re
 import binascii
+import crcmod.predefined
+import struct
 
 #DEVICE_HID_VID = 0x04d8
 #DEVICE_HID_PID = 0x0f32
@@ -10,6 +14,13 @@
 KIT_APP_COMMAND_SET_TIME = 0
 
 
+def kit_crc(data):
+    """Return bytes object of the crc based on the input data bytes"""
+    crc16 = crcmod.predefined.Crc('crc-16')
+    crc16.update(bytes(data))
+    return struct.pack('<H', int('{:016b}'.format(crc16.crcValue)[::-1], 2))
+
+
 class KitError(Exception):
     def __init__(self, error_info):
         self.error_code = error_info['error_code']
@@ -23,7 +34,7 @@ def __init__(self, device):
         self.report_size = 64
         self.next_app_cmd_id = 0
         self.app_responses = {}
-        self.kit_reply_regex = re.compile('^([0-9a-zA-Z]{2})\\(([^)]*)\\)')
+        self.kit_reply_regex = re.compile('([0-9a-zA-Z]{2})\\(([^)]*)\\)')
 
     def open(self, vendor_id=DEVICE_HID_VID, product_id=DEVICE_HID_PID):
         """Opens HID device for the Kit. Adjusts default VID/PID for the kit."""
@@ -58,7 +69,7 @@ def kit_read(self, timeout_ms=0):
         data = data[:data.index(10)+1] # Trim any data after the newline
         return ''.join(map(chr, data)) # Convert data from list of integers into string
 
-    def parse_kit_reply(self, data):
+    def kit_parse_reply(self, data):
         """Perform basic parsing of the kit protocol replies.
 
         - XX(YYZZ...)
@@ -68,3 +79,26 @@ def parse_kit_reply(self, data):
         if match is None:
             raise ValueError('Unable to parse kit protocol reply: %s' % data)
         return {'status': int(match.group(1), 16), 'data': match.group(2)}
+
+    def kit_list(self, idx):
+        """Request the address of the device associated with the index"""
+        self.kit_write('b:d', struct.pack("<B", idx))
+        return int(self.kit_parse_reply(self.kit_read(0))['data'], 16)
+
+    def kit_select(self, dev):
+        """Select the device with the given address"""
+        self.kit_write('e:p:s', struct.pack("<B", dev))
+        return self.kit_read(0)
+
+    def kit_command(self, opcode, param1, param2, data=b'', timeout_ms=0):
+        l2s = len(data) + 7     # length(1) + opcode(1) + param1(1) + param2(2) + crc(2)
+        # Make Packet
+        d2s = struct.pack("<BBBH", l2s, opcode, param1, param2)
+        # Append CRC
+        d2s += kit_crc(d2s)
+        # Send the command
+        self.kit_write('e:t', d2s)
+        # Get the response
+        resp = self.kit_read(timeout_ms=timeout_ms)
+        # Parse the response
+        return self.kit_parse_reply(resp)

scripts/at_pubkey.py

@@ -0,0 +1,21 @@
+#!/usr/bin/env python
+import hid
+from at_kit_base import *
+import base64
+
+# Initialize the Kit Instance
+dev = KitDevice(hid.device())
+dev.open()
+
+id = dev.kit_list(0)
+
+# Select the device to communicate with
+dev.kit_select(id)
+
+# Send the command
+resp = dev.kit_command(64, 0, 0, timeout_ms=5000)
+
+public_key = bytearray.fromhex('3059301306072A8648CE3D020106082A8648CE3D03010703420004') + bytearray.fromhex(resp['data'][2:-4])
+public_key = '-----BEGIN PUBLIC KEY-----\n' + base64.b64encode(public_key).decode('ascii') + '\n-----END PUBLIC KEY-----'
+
+print(public_key)

scripts/at_set_time.py

@@ -1,4 +1,4 @@
-#!/usr/bin/env python3
+#!/usr/bin/env python
 
 import hid
 import struct

scripts/requirements.txt

@@ -0,0 +1,3 @@
+crcmod
+cryptography
+hidapi