Changes between Version 3 and Version 4 of S6350serialcom

Timestamp:

10/27/08 11:38:29 (16 years ago)

Author:

pinwc4

Comment:

--

S6350serialcom

@@ -50 +50 @@
 The resulting command could look like this:
 ChrB(&h01) + ChrB(&h0D) + ChrB(&h00) + ChrB(&h00) + ChrB(&h00) + ChrB(&h00) + ChrB(&h60) + ChrB(&h11) + ChrB(&h27) + ChrB(&h01) + ChrB(&h00) + ChrB(&h5B) + ChrB(&hA4)
+
+= Silence Tag =
+
+The UID passed must be a string in the reverse byte order that it is recieved in the string assemled by this can be sent directly to the serial port to silence the given RFID tag
+
+dim silencecommand as string
+  
+Everything but checksum, portion before UID is the ISO15693 silence command for a TI S6350
+Byte 1 is the Start of Frame, always 01
+Byte 2 and 3 is the length of the command including the 2 byte check sum that is added to the end, Least Significant Byte first
+Byte 4 and 5 is the node address, leave at 00 as we do not reference nodes
+Byte 6 is the command flags, no flags present
+Byte 7 is the command, &h60 means it is an ISO15693 command which will be in the data portion of the packet
+Byte 8 is the config byte for the reader, &h11 means 100% modulation and 1/4 data mode
+Byte 9 is the ISO15693 command flags, &h23 means 2 sub carriers, high data rate, and address flag is set
+Byte 10 is the ISO15693 command, &h02 means be quiet
+Byte 11-18 are the UID that needs to shut up
+Byte 19 and 20 are the checksum that is added later
+
+An example would be:
+
+ChrB(&h01) + ChrB(&h14) + ChrB(&h00) + ChrB(&h00) + ChrB(&h00) + ChrB(&h00) + ChrB(&h60) + ChrB(&h11) + ChrB(&h23) + ChrB(&h02) + UID + Checksum
+  
+
+= Checksum =
+
+The checksum used by the TI S6350 is very basic.  It is a 2 byte checksum.  The first byte is the XOR of the string.  The second byte is teh XOR of &hFF and the first byte.
+
+Here is an example of the code to do this:
+  
+  dim checksum as string
+  dim xornumber1 as integer
+  dim xornumber2 as integer
+  
+  'Do a XOR of all the bytes of the string for byte 1 of the checksum
+  'Do not worry about xornumber having a zero initially, this does not impact the XOR operation
+  for i as Integer=1 to len(data)
+    xornumber1 = xornumber1 xor ascB(mid(data,i,1))
+  next
+  
+  'calculates byte 2 of the checksum
+  xornumber2 = &hFF xor xornumber1
+  
+  'put the two together for the complete checksum
+  checksum = chrB(xornumber1) + chrB(xornumber2)