You said initially that Wire.endTransmission(); caused the USB reset, even with nothing attached to the Arduino. I am trying to get past that point for you. Does that happen or not?
Yes that is true. However, I just got past this whole issue now. For the USB reset (noise) not to happen I need the SDA and SCL lines tied to Vdd (+5v) and use of a 4.7K resistor on each line. This is just using the Arduino Uno R3 board and no other boards stacked.
Now that this is working, I'm going to introduce more of the original code. Currently, I'm stuck at the following while loop in the i2cRead16 function. Any help here?
while (Wire.available() < 2)
;
ORIGINAL CODE:
/* LiPower Shield Example Code
by: Jim Lindblom
SparkFun Electronics
date: 1/3/12
*/
#include <Wire.h>
#define MAX17043_ADDRESS 0x36 // R/W =~ 0x6D/0x6C
// Pin definitions
int alertPin = 2; // This is the alert interrupt pin, connected to pin 2 on the LiPower Shield
// Global Variables
float batPercentage;
//float batVoltage;
//int alertStatus;
void setup()
{
pinMode(alertPin, INPUT);
digitalWrite(alertPin, HIGH);
Serial.begin(9600); // Start hardware serial
Serial.println("Start Wire.begin() (i2c bus) in 5 seconds");
delay(5000);
Wire.begin(); // Start I2C
Serial.println("Wire.begin() has executed");
Serial.println("Start configMax in 5 seconds");
delay(5000);
configMAX17043(32); // Configure the MAX17043's alert percentage
Serial.println("configMax function has executed");
Serial.println("Start qsMAX17043 in 5 seconds");
delay(5000);
qsMAX17043(); // restart fuel-gauge calculations
Serial.println("qsMAX17043 function has executed");
}
void loop()
{
Serial.println("Start percentMAX17043() in 5 seconds");
delay(5000);
batPercentage = percentMAX17043();
Serial.println("percentMAX17043 function has executed");
//batVoltage = (float) vcellMAX17043() * 1/800; // vcell reports battery in 1.25mV increments
//alertStatus = digitalRead(alertPin);
delay(3000);
Serial.print(batPercentage, 2); // Print the battery percentage
Serial.println(" % battery life");
// Serial.print(batVoltage, 2); // print battery voltage
// Serial.println(" battery's voltage");
// Serial.print("Alert Status = ");
// Serial.println(alertStatus, DEC);
Serial.println();
delay(1000);
}
/*
vcellMAX17043() returns a 12-bit ADC reading of the battery voltage,
as reported by the MAX17043's VCELL register.
This does not return a voltage value. To convert this to a voltage,
multiply by 5 and divide by 4096.
*/
/*
unsigned int vcellMAX17043()
{
unsigned int vcell;
vcell = i2cRead16(0x02);
vcell = vcell >> 4; // last 4 bits of vcell are nothing
return vcell;
}
*/
/*
percentMAX17043() returns a float value of the battery percentage
reported from the SOC register of the MAX17043.
*/
float percentMAX17043()
{
unsigned int soc;
float percent;
Serial.println("made it inside percentMAX17043 function");
Serial.println("wait 5 seconds to call i2cRead16(0x04)");
delay(5000);
soc = i2cRead16(0x04); // Read SOC register of MAX17043
percent = (byte) (soc >> 8); // High byte of SOC is percentage
percent += ((float)((byte)soc))/256; // Low byte is 1/256%
return percent;
}
/*
configMAX17043(byte percent) configures the config register of
the MAX170143, specifically the alert threshold therein. Pass a
value between 1 and 32 to set the alert threshold to a value between
1 and 32%. Any other values will set the threshold to 32%.
*/
void configMAX17043(byte percent)
{
if ((percent >= 32)||(percent == 0)) // Anything 32 or greater will set to 32%
i2cWrite16(0x9700, 0x0C);
else
{
byte percentBits = 32 - percent;
i2cWrite16((0x9700 | percentBits), 0x0C);
}
}
/*
qsMAX17043() issues a quick-start command to the MAX17043.
A quick start allows the MAX17043 to restart fuel-gauge calculations
in the same manner as initial power-up of the IC. If an application's
power-up sequence is very noisy, such that excess error is introduced
into the IC's first guess of SOC, the Arduino can issue a quick-start
to reduce the error.
*/
void qsMAX17043()
{
Serial.println("made it inside qsMAX17043 function");
Serial.println("wait 5 seconds to call i2cWrite16(0x4000, 0x06)");
delay(5000);
i2cWrite16(0x4000, 0x06); // Write a 0x4000 to the MODE register
Serial.println("you've made it thru i2cWrite16(0x4000, 0x06)");
delay(5000);
}
/*
i2cRead16(unsigned char address) reads a 16-bit value beginning
at the 8-bit address, and continuing to the next address. A 16-bit
value is returned.
*/
unsigned int i2cRead16(unsigned char address)
{
int data = 0;
Serial.println("you've made it inside i2cRead16 function");
Serial.println("wait 5 seconds to begin transmission");
delay(5000);
Wire.beginTransmission(MAX17043_ADDRESS);
Serial.println("beginTransmission has completed");
Serial.println("wait 5 seconds to write to buffer");
delay(5000);
Wire.write(address);
Serial.println("write to buffer has completed");
Serial.println("wait 5 seconds to end transmission");
delay(5000);
Wire.endTransmission();
Serial.println("you've made it past Wire.endTransmission()");
//stuck here right now!!!
Serial.println("wait 5 seconds to requestFrom 17043 address 2 bytes");
delay(5000);
Wire.requestFrom(MAX17043_ADDRESS, 2);
Serial.println("you've made it past requestFrom 17043 address 2 bytes");
Serial.println("wait 5 seconds to enter while(Wire.available()<2)");
delay(5000);
while (Wire.available() < 2)
;
Serial.println("you've made it past while(Wire.available()<2)");
Serial.println("wait 5 seconds to call Wire.read()");
delay(5000);
data = ((int) Wire.read()) << 8;
data |= Wire.read();
Serial.println("you've made it past Wire.read()");
Serial.println("wait 5 seconds to return data");
delay(5000);
return data;
Serial.println("you've made it past return data");
}
/*
i2cWrite16(unsigned int data, unsigned char address) writes 16 bits
of data beginning at an 8-bit address, and continuing to the next.
*/
// 0x9700 = 38656, 0x0C is the config register (memory)
void i2cWrite16(unsigned int data, unsigned char address)
{
Serial.println("made it inside i2cWrite16 function");
Serial.println("wait 5 seconds to begin transmission");
delay(5000);
Wire.beginTransmission(MAX17043_ADDRESS);
Serial.println("beginTransmission has completed");
Serial.println("wait 5 seconds to write to buffer");
delay(5000);
Wire.write(address);
Wire.write((byte)((data >> 8) & 0x00FF));
Wire.write((byte)(data & 0x00FF));
Serial.println("write to buffer has completed");
Serial.println("wait 5 seconds to end transmission");
delay(5000);
Wire.endTransmission();
Serial.println("you've made it past Wire.endTransmission()");
}
OUTPUT:
Start Wire.begin() (i2c bus) in 5 seconds
Wire.begin() has executed
Start configMax in 5 seconds
made it inside i2cWrite16 function
wait 5 seconds to begin transmission
beginTransmission has completed
wait 5 seconds to write to buffer
write to buffer has completed
wait 5 seconds to end transmission
you've made it past Wire.endTransmission()
configMax function has executed
Start qsMAX17043 in 5 seconds
made it inside qsMAX17043 function
wait 5 seconds to call i2cWrite16(0x4000, 0x06)
made it inside i2cWrite16 function
wait 5 seconds to begin transmission
beginTransmission has completed
wait 5 seconds to write to buffer
write to buffer has completed
wait 5 seconds to end transmission
you've made it past Wire.endTransmission()
you've made it thru i2cWrite16(0x4000, 0x06)
qsMAX17043 function has executed
Start percentMAX17043() in 5 seconds
made it inside percentMAX17043 function
wait 5 seconds to call i2cRead16(0x04)
you've made it inside i2cRead16 function
wait 5 seconds to begin transmission
beginTransmission has completed
wait 5 seconds to write to buffer
write to buffer has completed
wait 5 seconds to end transmission
you've made it past Wire.endTransmission()
wait 5 seconds to requestFrom 17043 address 2 bytes
you've made it past requestFrom 17043 address 2 bytes
wait 5 seconds to enter while(Wire.available()<2)
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