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--- project:weathersonde:eeprom_mgmt [2015/02/01 13:35] – created jenda
+++ project:weathersonde:eeprom_mgmt [2018/10/01 13:48] (current) – pinky
@@ Line 1: / Line 1: @@
 ====== Arduino sketch for control via SPI ======
-Dear Brmlab Staff!
 I've recovered two weather sondes with my friend, and played with them. Googled, and the result is a simple program run on an Arduino (I had a mega2560 lying around...).
@@ Line 14: / Line 12: @@
 Save button: saves the changes to the sonde EEPROM.
-Please, put this attached code on the Weather Sonde subpage.
 Thanks, and have a nice day, Peter from Budapest, Hungary
-<code>
+==== connection note ====
-/*
+This post was send by email, if You have difficulty to read/write eeprom, try this
+I've managed to solve it. Please let my now if You find any incorrectness.
+It turned to be some weird voltage translation stuff. When the onboard CPU is in reset, the SCK and MOSI lines are held low (0V) by a relatively low impedance (about 250R, but the I-V curve is nonlinear), and the CS is held high (2.85V) by low impedance (about 300R, I-V curve non-linear). The MISO line is truly floating or connected to very highimpedance. I've used 100R series resistors on the SCK and MOSI lines. This gives me around 3V on the EEPROM pins when the Arduino is driving this lines high to 5V. When the Arduino drives this lines low to 0V, I get 0V on the other side as well.
+ The CS is more problematic, because a low enough series resistor to make the Arduino drive it low effectively will make the voltage too high when the Arduino drives it to 5V. Therefore, I've connected this line to the collector of an NPN transistor. The emitter is grounded and the base is conected through 1k to the CS pin of the Arduino. I drive the CS pin on the Arduino in an inverted fashion. Thus, the NPN transistor pulls the EEPROM CS to ground when CS is active and the rest of the time the EEPROM CS is pulled high by the onboard CPU.  With this setup I'm starting to get data out of the EEPROM.
+ Regards,
+  Daniel.
+===== Code =====
+<code>
+/*
  Connect an LCD display to the Arduino. Connect the Vaisala RS92 to the SPI port, connect the SS pin to a digital output.
  Pins are user configurable! Don't forget, that the project can be run on any types of Arduino. I had a Mega 2560 lying around,
@@ Line 34: / Line 44: @@
  Button 3: change transmitter state, Arduino PIN 4
  Button 4: save to Vaisala RS92, Arduino PIN 5
  PIN connections of the Vaisala service connector (edge connector, PIN1 is downside left, when the Vaisala is standing on the battery side).
  Source: https://brmlab.cz/project/weathersonde/hw
 - GND, connect to Arduino GND
 - VCC, connect to Arduino VCC input. Maximum allowed: 12V
@@ Line 55: / Line 63: @@
  (c) Peter Thiering 2015, thieringpeti@gmail.com
  */
@@ Line 96: / Line 103: @@
   lcd.begin(16, 2);
   // Print a message to the LCD.
   // initalize the  data ready and chip select pins:
@@ Line 117: / Line 123: @@
   readData();
   displayData();
 }
 void readData(void)
 {
   digitalWrite(CSPin, LOW);
   // send the device the register you want to read:
@@ Line 133: / Line 135: @@
   // send a value of 0 to read the first byte returned:
   digitalWrite(CSPin,HIGH);
   // read freq
   digitalWrite(CSPin,LOW);
@@ Line 145: / Line 144: @@
   f1 = SPI.transfer(0x00);
   f2 = SPI.transfer(0x00);
   digitalWrite(CSPin,HIGH);
@@ Line 151: / Line 149: @@
 void displayData(void)
 {
   lcd.setCursor(0, 1);
@@ Line 163: / Line 160: @@
   if (data == 0x03) lcd.print("TX Energy Saving");
   if (data > 0x03) lcd.print("bad TX data     ");
   freq = f1*10 + f2 * 2560 + 400000;
   lcd.setCursor(6, 1);
   lcd.print(freq);
 }
 void scanButtons(void)
 {
   int plusbutton = !digitalRead(PLUS);
   int minusbutton = !digitalRead(MINUS);
@@ Line 181: / Line 174: @@
   while ((plusbutton || minusbutton || pwrbutton || savebutton) == 0)
   {
     plusbutton = !digitalRead(PLUS);
@@ Line 187: / Line 179: @@
     pwrbutton = !digitalRead(TXPWR);
     savebutton = !digitalRead(SAVE);
   }
   if (plusbutton)
   {
     if (f1 == 0xff)
@@ Line 207: / Line 194: @@
       f1 += 1;
     }
   }
   if (minusbutton)
   {
     if (f1 == 0)
@@ Line 224: / Line 209: @@
       f1 -= 1;
     }
   }
@@ Line 230: / Line 214: @@
   {
     switch (data)
     {
     case 0:
@@ Line 248: / Line 231: @@
       break;
     }
   }
   lcd.setCursor(19,0);
   lcd.print("*");
   if (savebutton)
   {
     saveData();
     lcd.setCursor(19,0);
     lcd.print("S");
   }
@@ Line 279: / Line 255: @@
 void saveData(void)
 {
     digitalWrite(CSPin, LOW);
-  SPI.transfer(WRSR);
+    SPI.transfer(WRSR);
-  SPI.transfer(0x02);
+    SPI.transfer(0x02);
-   digitalWrite(CSPin,HIGH);
+    digitalWrite(CSPin,HIGH);
-  digitalWrite(CSPin, LOW);
+    digitalWrite(CSPin, LOW);
-  SPI.transfer(WREN);
+    SPI.transfer(WREN);
-   digitalWrite(CSPin,HIGH);
+    digitalWrite(CSPin,HIGH);
-   delay(10);
+    delay(10);
-digitalWrite(CSPin, LOW);
+    digitalWrite(CSPin, LOW);
   // send the device the register you want to read:
   SPI.transfer(WRITE);
@@ Line 299: / Line 274: @@
   // send a value of 0 to read the first byte returned:
   digitalWrite(CSPin,HIGH);
   delay(100);
@@ Line 305: / Line 279: @@
     digitalWrite(CSPin, LOW);
-  SPI.transfer(WRSR);
+    SPI.transfer(WRSR);
-  SPI.transfer(0x02);
+    SPI.transfer(0x02);
-   digitalWrite(CSPin,HIGH);
+    digitalWrite(CSPin,HIGH);
-  digitalWrite(CSPin, LOW);
+    digitalWrite(CSPin, LOW);
-  SPI.transfer(WREN);
+    SPI.transfer(WREN);
-   digitalWrite(CSPin,HIGH);
+    digitalWrite(CSPin,HIGH);
-   delay(100);
+    delay(100);
-  digitalWrite(CSPin,LOW);
+    digitalWrite(CSPin,LOW);
   SPI.transfer(WRITE);
   SPI.transfer(VAISALA_CONFIG);
@@ Line 334: / Line 308: @@
   SPI.transfer(f2);
   digitalWrite(CSPin,HIGH);
 }
 void loop() {
   scanButtons();
   delay(20);