Zbernica i2c: nástroje II.: Rozdiel medzi revíziami
Z SensorWiki
(Vytvorená stránka „Niekoľko užitočných programov k zbernici i2c. Nech poslúžia na štúdium a tvorbu vlastných pokusov. Príklady sú doplnkom cvičenia s obvodom AT24C02 - pamä...“) |
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Riadok 68: | Riadok 68: | ||
+ | </source> | ||
+ | |||
+ | |||
+ | == Výpis celého obsahu pamäte == | ||
+ | |||
+ | <source lang="c"> | ||
+ | #include <Wire.h> | ||
+ | #define M24C02 (0xA0>>1) | ||
+ | void setup() | ||
+ | { | ||
+ | Wire.begin(); // join i2c bus (address optional for master) | ||
+ | Serial.begin(9600); // start serial for output | ||
+ | Serial.println("Vypis pamate M24C02:"); | ||
+ | Serial.println("--------------------"); | ||
+ | |||
+ | Wire.beginTransmission(M24C02); // part address is 0xA0 | ||
+ | Wire.write(0x00); // | ||
+ | Wire.endTransmission(); | ||
+ | |||
+ | delay(1); | ||
+ | |||
+ | for (int i=0;i<=7; i++) | ||
+ | { | ||
+ | Serial.print(i,HEX); | ||
+ | Serial.print(": "); | ||
+ | |||
+ | // tuto moze byt max. 32, aj ked dam viac, nevrati viac nez 32 | ||
+ | // adresa 0xA0 je pre Arduino len 50 (lebo 7 bitov?) | ||
+ | Wire.requestFrom(M24C02, 255); // request 6 bytes from slave device #2 | ||
+ | while(Wire.available()) // slave may send less than requested | ||
+ | { | ||
+ | char c = Wire.read(); // receive a byte as character | ||
+ | Serial.print(c); // print the character | ||
+ | } | ||
+ | Serial.println(" --------------"); | ||
+ | } | ||
+ | |||
+ | } | ||
+ | |||
+ | void loop() | ||
+ | { | ||
+ | |||
+ | } | ||
+ | |||
+ | |||
+ | </source> | ||
+ | |||
+ | == Preskenovanie zbernice a nájdenie obvodov == | ||
+ | |||
+ | <source lang="c"> | ||
+ | #include <Wire.h> | ||
+ | |||
+ | |||
+ | void setup() | ||
+ | { | ||
+ | Wire.begin(); | ||
+ | |||
+ | Serial.begin(9600); | ||
+ | Serial.println("\nI2C Scanner"); | ||
+ | } | ||
+ | |||
+ | |||
+ | void loop() | ||
+ | { | ||
+ | byte error, address; | ||
+ | int nDevices; | ||
+ | |||
+ | Serial.println("Scanning..."); | ||
+ | |||
+ | nDevices = 0; | ||
+ | for(address = 1; address < 127; address++ ) | ||
+ | { | ||
+ | // The i2c_scanner uses the return value of | ||
+ | // the Write.endTransmisstion to see if | ||
+ | // a device did acknowledge to the address. | ||
+ | Wire.beginTransmission(address); | ||
+ | error = Wire.endTransmission(); | ||
+ | |||
+ | if (error == 0) | ||
+ | { | ||
+ | Serial.print("I2C device found at address 0x"); | ||
+ | if (address<16) | ||
+ | Serial.print("0"); | ||
+ | Serial.print(address,HEX); | ||
+ | Serial.println(" !"); | ||
+ | |||
+ | nDevices++; | ||
+ | } | ||
+ | else if (error==4) | ||
+ | { | ||
+ | Serial.print("Unknow error at address 0x"); | ||
+ | if (address<16) | ||
+ | Serial.print("0"); | ||
+ | Serial.println(address,HEX); | ||
+ | } | ||
+ | } | ||
+ | if (nDevices == 0) | ||
+ | Serial.println("No I2C devices found\n"); | ||
+ | else | ||
+ | Serial.println("done\n"); | ||
+ | |||
+ | delay(5000); // wait 5 seconds for next scan | ||
+ | } | ||
</source> | </source> |
Verzia zo dňa a času 20:43, 6. máj 2017
Niekoľko užitočných programov k zbernici i2c. Nech poslúžia na štúdium a tvorbu vlastných pokusov.
Príklady sú doplnkom cvičenia s obvodom AT24C02 - pamäť EEPROM.
Základný zápis a čítanie podľa návodu
#include <Wire.h>
#define deviceAddress B01010000
void setup()
{
Serial.begin(9600);
Wire.begin();
/* Zapiseme do EEPROM niekolko znakov */
for (int i = 0; i < 10; i++)
{
eeprom_i2c_write(deviceAddress, i, 'A'+i);
delay(100); /* lebo zapis chvilu trva a nekontrolujeme ACK */
}
Serial.println("Writen to memory!");
}
void loop()
{
byte myData;
for (int memAddress = 0; memAddress < 20; memAddress++)
{
myData = eeprom_i2c_read(deviceAddress, memAddress);
Serial.print(memAddress);
Serial.print(" - ");
Serial.print((char)myData);
Serial.print("\n");
delay(100);
}
delay(2000);
}
void eeprom_i2c_write(byte address, byte from_addr, byte data) {
Wire.beginTransmission(address);
Wire.write(from_addr);
Wire.write(data);
Wire.endTransmission();
}
byte eeprom_i2c_read(int address, int from_addr) {
byte result=0xFF; // ak nic neprijmeme, tak vrati FF
Wire.beginTransmission(address);
Wire.write(from_addr);
Wire.endTransmission();
Wire.requestFrom(address, 1);
if(Wire.available())
result = Wire.read();
Wire.endTransmission();
return result;
}
Výpis celého obsahu pamäte
#include <Wire.h>
#define M24C02 (0xA0>>1)
void setup()
{
Wire.begin(); // join i2c bus (address optional for master)
Serial.begin(9600); // start serial for output
Serial.println("Vypis pamate M24C02:");
Serial.println("--------------------");
Wire.beginTransmission(M24C02); // part address is 0xA0
Wire.write(0x00); //
Wire.endTransmission();
delay(1);
for (int i=0;i<=7; i++)
{
Serial.print(i,HEX);
Serial.print(": ");
// tuto moze byt max. 32, aj ked dam viac, nevrati viac nez 32
// adresa 0xA0 je pre Arduino len 50 (lebo 7 bitov?)
Wire.requestFrom(M24C02, 255); // request 6 bytes from slave device #2
while(Wire.available()) // slave may send less than requested
{
char c = Wire.read(); // receive a byte as character
Serial.print(c); // print the character
}
Serial.println(" --------------");
}
}
void loop()
{
}
Preskenovanie zbernice a nájdenie obvodov
#include <Wire.h>
void setup()
{
Wire.begin();
Serial.begin(9600);
Serial.println("\nI2C Scanner");
}
void loop()
{
byte error, address;
int nDevices;
Serial.println("Scanning...");
nDevices = 0;
for(address = 1; address < 127; address++ )
{
// The i2c_scanner uses the return value of
// the Write.endTransmisstion to see if
// a device did acknowledge to the address.
Wire.beginTransmission(address);
error = Wire.endTransmission();
if (error == 0)
{
Serial.print("I2C device found at address 0x");
if (address<16)
Serial.print("0");
Serial.print(address,HEX);
Serial.println(" !");
nDevices++;
}
else if (error==4)
{
Serial.print("Unknow error at address 0x");
if (address<16)
Serial.print("0");
Serial.println(address,HEX);
}
}
if (nDevices == 0)
Serial.println("No I2C devices found\n");
else
Serial.println("done\n");
delay(5000); // wait 5 seconds for next scan
}