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56 lines
1.4 KiB
56 lines
1.4 KiB
// Wire Master Reader
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// by Nicholas Zambetti <http://www.zambetti.com>
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// Demonstrates use of the Wire library
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// Reads data from an I2C/TWI slave device
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// Refer to the "Wire Slave Sender" example for use with this
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// Created 29 March 2006
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// This example code is in the public domain.
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// modified by Alan Johnston to show reading registers 0 - 3
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// code based on https://forum.arduino.cc/index.php?topic=211587.0
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//
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// This code is to simulate the Raspberry Pi acting as I2C bus master
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#include <Wire.h>
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#define I2C_ADDRESS 0x4B
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#define REGISTER_0 0x00
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#define REGISTER_1 0x01
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#define REGISTER_2 0x02
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#define REGISTER_3 0x03
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uint8_t reg; // I2C read register
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void setup() {
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Wire.begin(); // join i2c bus (address optional for master)
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Serial.begin(9600); // start serial for output
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pinMode(LED_BUILTIN, OUTPUT);
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Serial.println("Starting");
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}
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void loop() {
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for (reg=0; reg < 4; reg++) {
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delay(5000);
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digitalWrite(LED_BUILTIN, HIGH);
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Wire.beginTransmission(I2C_ADDRESS);
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Wire.write(reg);
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Wire.endTransmission();
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delay(100);
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digitalWrite(LED_BUILTIN, LOW);
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Wire.requestFrom(I2C_ADDRESS, 2); // request 2 bytes from I2C device
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byte LSB = Wire.read();
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byte MSB = Wire.read();
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uint16_t register_value = ((MSB << 8) | LSB);
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Serial.print("Read ");
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Serial.print(register_value, HEX); // display register value in HEXADECIMAL
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Serial.print(" from register ");
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Serial.println(reg);
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}
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}
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