commit 60fa09d29815d8eaff21e1c82322ba4838ee8e38
Author: Dmitry Isaenko <developer.su@gmail.com>
Date:   Sat Sep 11 18:58:49 2021 +0300

    share this

diff --git a/.gitignore b/.gitignore
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+util
+OneWire.cpp
+OneWire.h
\ No newline at end of file
diff --git a/LICENSE b/LICENSE
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+           DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
+                   Version 2, December 2004
+
+Copyright (C) 2004 Sam Hocevar <sam@hocevar.net>
+
+Everyone is permitted to copy and distribute verbatim or modified
+copies of this license document, and changing it is allowed as long
+as the name is changed.
+
+           DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
+  TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
+
+ 0. You just DO WHAT THE FUCK YOU WANT TO.
diff --git a/README.MD b/README.MD
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+# arduino_rw1990 
+
+Read and flash RW1990 keys using arduino.
+
+RW1990 aka RW-1990. Most likely RW-1990.1, ТМ-08, ТМ-08v2 will be working.
+
+### It should be something about 'PCB'
+
+You will need:
+* Resistor 2.2k
+* Arduino Nano. Or not Nano, Uno is also good. Or you can pick some Arduino-compatible board.
+* Wires x3
+
+Long story short: pull PIN 10 over capacitor to VCC. Plug this pin to the center of the iButton key. Key 'borders' should be connected to the ground.
+
+Just take a look on [what_is_it_should_be_look_like.jpg](what_is_it_should_be_look_like.jpg)
+
+### HOWTO 
+
+To ***read key*** just flash snipped as is.
+
+To ***write key*** you need do next steps:
+
+1. Set `key_to_write` to key you want to write.
+2. Find in code '// UNCOMMENT THIS SECTION FOR FLASHING KEY' section and uncomment this section.
+3. Flash. Check. Get satisfied.
+
+### Example
+
+```
+
+```
+
+### References:
+
+Uses some code, ideas, information, inspiration taken from:
+* https://github.com/AlexMalov/EasyKeyDublicator/
+* https://habr.com/ru/post/237487/
+
+### License
+
+Since I didn't find any license info in projects used please consider this as WTFPL app.
\ No newline at end of file
diff --git a/arduino_rw1990.ino b/arduino_rw1990.ino
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+/*
+* NOTE: Button center is positive wire. Borders eq. ground
+*/
+
+#include "OneWire.h"
+
+#define used_pin 10
+#define _DEBUG
+
+// KEY_TO_WRITE. SET KEY YOU WANNA WRITE RIGHT HERE
+byte key_to_write[] = { 0x01, 0x5F, 0x69, 0xB, 0x1, 0x0, 0x0, 0xEA };
+
+OneWire  ds(used_pin);  // pin 10 is 1-Wire interface pin now
+
+void setup(void) {
+  Serial.begin(9600);
+}
+
+void loop(void) {
+  byte i;
+  byte read_data[8];
+
+  delay(1000); // 1 sec
+  
+  read_key(read_data);
+  
+  if (print_key_connected_status(read_data))
+    return;
+  
+  print_key(read_data, 8);
+  
+  if (validate_key(read_data))
+    return;
+  
+  if (!checkTypeRW1990()){
+    Serial.println("Not RW1990. Not supported.");
+    return;
+  }
+  // UNCOMMENT THIS SECTION FOR FLASHING KEY
+  /*
+  flash(); 
+  read_key(read_data);
+  print_key(read_data, 8);
+  */
+}
+
+void read_key(byte* read_data){ 
+  ds.reset();
+  ds.write(0x33); // "READ" command
+  ds.read_bytes(read_data, 8);
+}
+boolean print_key_connected_status(byte read_data[]){
+  // Check if FF:FF:FF:FF:FF:FF:FF:FF . MOST LIKELY (but not always) NOTHING IS PLUGGED IN
+  if (read_data[0] & read_data[1] & read_data[2] & read_data[3] & read_data[4] & read_data[5] & read_data[6] & read_data[7] == 0xFF){
+    Serial.print("."); 
+    return true;
+  }
+  return false;
+}
+
+void print_key(byte *key_array, int size){
+  Serial.println();
+  Serial.print("[");
+  for(int i = 0; i < size; i++) {
+    Serial.print(key_array[i], HEX);
+    if (i != 7) 
+      Serial.print(":");
+  }
+  Serial.println("]");
+}
+
+boolean validate_key(byte read_data[]){
+  // Check if read key is equal to one that has to be programmed
+  for (int i = 0; i < 8; i++){
+    if (read_data[i] != key_to_write[i])
+        return false;
+  }
+  Serial.print(" programmed to KEY requested");
+  return true;
+}
+
+boolean checkTypeRW1990(){
+  ds.reset();
+  ds.write(0xD1);          // attend to remove write flag
+  ds.write_bit(1);
+  delay(10);
+  pinMode(used_pin, INPUT); 
+
+  ds.reset();
+  ds.write(0xB5);          // Request write flag stat
+  byte reply = ds.read();
+  #ifdef DEBUG
+  Serial.print("Reply RW-1990.1: "); 
+  Serial.println(reply, HEX);
+  #endif
+  if (reply == 0xFE)       // 0xFE eq. RW-1990, RW-1990.1, ТМ-08, ТМ-08v2 
+    return true;
+  return false;
+}
+
+void flash(){
+  ds.reset();
+  ds.write(0xD1);                    // write command
+  ds.write_bit(0);
+  delay(10);
+  pinMode(used_pin, INPUT); 
+  ds.reset();
+  ds.write(0xD5);     
+  for (byte i = 0; i < 8; i++){
+    BurnByte(~key_to_write[i]);      // invert 4 RW1990.1
+    Serial.print('+');
+  } 
+  
+  ds.write(0xD1);                         // write flag
+  ds.write_bit(1);                        // stop
+  pinMode(used_pin, INPUT); 
+  delay(10);
+}
+
+void BurnByte(byte data){
+  for(byte n_bit = 0; n_bit < 8; n_bit++){ 
+    ds.write_bit(data & 1);  
+    delay(5);                        // даем время на прошивку каждого бита до 10 мс
+    data = data >> 1;                // переходим к следующему bit
+  }
+  pinMode(used_pin, INPUT);
+}
diff --git a/what_is_it_should_be_look_like.jpg b/what_is_it_should_be_look_like.jpg
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