Other Parts Discussed in Thread: LP5860, MSP430F5529
The Arduino nano provides SDA and SCL for I2C connectivity. The LP5868 has a lot of registers and requires 10-bit addresses to select them. Arduino I2C libraries are generally 8-bit address implementations. Texas Instruments tech support tells me that Arduino libraries do not exist to drive the LP5868.
So I wrote Arduino IDE test code that manually manipulates SDA and SCL and switches SDA between input mode and output mode for ACKS and for reads and writes to the slave device. The hardware config is an LP5868 with its SCL and SDA pins connected to the SCL and SDA on the nano respectively, with 4.7K ohm pull-up resistors to +5V.
My interface is not working. The logic analyzer capture explains what I am seeing. This is a capture of me writing a value 1 to register 0 on the LP5868, and then reading back the value of register 0.
Any input including choice of an alternate microcontroller, logic or any other errors is appreciated.
The nano test code is:
#define numMicroseconds 1000
//#define SCL 19
//#define SDA 18
byte binaryValue = 0b11010110; // binary value to extract bit from
byte extractedBit = (binaryValue >> 2) & 0x01; // extract third bit (bit index starts from 0)
void setup() {
Serial.begin(9600);
while (!Serial);
Serial.print(F("\tSDA = ")); Serial.println(SDA);
Serial.print(F("\tSCL = ")); Serial.println(SCL);
}
void loop()
{
//write
pinMode(SDA,OUTPUT);
pinMode(SCL,OUTPUT);
//start
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SDA, LOW);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
binaryValue = 0b10101000;
for (int i = 7; i >=0; i--) {
extractedBit = (binaryValue >> i) & 0x01;
if(extractedBit==1) {
digitalWrite(SDA, HIGH);
} else {
digitalWrite(SDA, LOW);
}
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
}
pinMode(SDA,INPUT);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
pinMode(SDA,OUTPUT);
delayMicroseconds(numMicroseconds);
binaryValue = 0b00000000;
for (int i = 7; i >=0; i--) {
extractedBit = (binaryValue >> i) & 0x01;
if(extractedBit==1) {
digitalWrite(SDA, HIGH);
} else {
digitalWrite(SDA, LOW);
}
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
}
pinMode(SDA,INPUT);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
pinMode(SDA,OUTPUT);
delayMicroseconds(numMicroseconds);
binaryValue = 0b00000001;
for (int i = 7; i >=0; i--) {
extractedBit = (binaryValue >> i) & 0x01;
if(extractedBit==1) {
digitalWrite(SDA, HIGH);
} else {
digitalWrite(SDA, LOW);
}
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
}
pinMode(SDA,INPUT);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
pinMode(SDA,OUTPUT);
delayMicroseconds(numMicroseconds);
//stop
digitalWrite(SDA, LOW);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SDA, HIGH);
delay(10); // wait
//read
pinMode(SDA,OUTPUT);
pinMode(SCL,OUTPUT);
//start
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SDA, LOW);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
binaryValue = 0b10101001;
for (int i = 7; i >=0; i--) {
extractedBit = (binaryValue >> i) & 0x01;
if(extractedBit==1) {
digitalWrite(SDA, HIGH);
} else {
digitalWrite(SDA, LOW);
}
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
}
pinMode(SDA,INPUT);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
pinMode(SDA,OUTPUT);
delayMicroseconds(numMicroseconds);
binaryValue = 0b00000000;
for (int i = 7; i >=0; i--) {
extractedBit = (binaryValue >> i) & 0x01;
if(extractedBit==1) {
digitalWrite(SDA, HIGH);
} else {
digitalWrite(SDA, LOW);
}
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
}
pinMode(SDA,INPUT);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
// pinMode(SDA,OUTPUT);
delayMicroseconds(numMicroseconds);
for (int i = 7; i >=0; i--) {
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
}
pinMode(SDA,OUTPUT);
delayMicroseconds(numMicroseconds);
digitalWrite(SDA, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, LOW);
delayMicroseconds(numMicroseconds);
digitalWrite(SDA, LOW);
delayMicroseconds(numMicroseconds);
pinMode(SDA,OUTPUT);
delayMicroseconds(numMicroseconds);
//stop
digitalWrite(SDA, LOW);
delayMicroseconds(numMicroseconds);
digitalWrite(SCL, HIGH);
delayMicroseconds(numMicroseconds);
digitalWrite(SDA, HIGH);
delay(1000); // wait
}
