How to control an Mcp41010 wiper position with an analog value - arduino

Question

I am using an Mcp41010 digipot chip and am wondering how to vary the wiper position of the chip with an analog input voltage that I can adjust, I need a way of decrementing(--) the wiper position if the voltage goes over a certain point and incrementing(++) the wiper position of the chip back to the normal position this is some code that i found that just fades the wiper position up and down I need a way of controlling it. I am still very new to arduino so sorry if my explanation was clear enough.
int CS_signal = 12; // Chip Select signal onsul pin 2 of Arduino
int CLK_signal = 52; // Clock signal on pin 4 of Arduino
int MOSI_signal = 51; // MOSI signal on pin 5 of Arduino
byte cmd_byte2 = B00010001 ; // Command byte
int initial_value = 100; // Setting up the initial value
void initialize() { // send the command byte of value 100 (initial value)
spi_out(CS_signal, cmd_byte2, initial_value);
}
void spi_out(int CS, byte cmd_byte, byte data_byte){ // we need this function to send command byte and data byte to the chip
digitalWrite (CS, LOW); // to start the transmission, the chip select must be low
spi_transfer(cmd_byte); // invio il COMMAND BYTE
delay(2);
spi_transfer(data_byte); // invio il DATA BYTE
delay(2);
digitalWrite(CS, HIGH); // to stop the transmission, the chip select must be high
}
void spi_transfer(byte working) {
for(int i = 1; i <= 8; i++) { // Set up a loop of 8 iterations (8 bits in a byte)
if (working > 127) {
digitalWrite (MOSI_signal,HIGH) ; // If the MSB is a 1 then set MOSI high
} else {
digitalWrite (MOSI_signal, LOW) ; } // If the MSB is a 0 then set MOSI low
digitalWrite (CLK_signal,HIGH) ; // Pulse the CLK_signal high
working = working << 1 ; // Bit-shift the working byte
digitalWrite(CLK_signal,LOW) ; // Pulse the CLK_signal low
}
}
void setup() {
pinMode (CS_signal, OUTPUT);
pinMode (CLK_signal, OUTPUT);
pinMode (MOSI_signal, OUTPUT);
initialize();
Serial.begin(9600); // setting the serial speed
Serial.println("ready!");
}
void loop() {
for (int i = 0; i < 255; i++) {
spi_out(CS_signal, cmd_byte2, i);
Serial.println(i); delay(10);
}
for (int i = 255; i > 0; --i) {
spi_out(CS_signal, cmd_byte2, i);
Serial.println(i);
delay(10);
}
}

Answer 1

int CS_signal = 12; // Chip Select signal onsul pin 2 of Arduino
int CLK_signal = 52; // Clock signal on pin 4 of Arduino
int MOSI_signal = 51; // MOSI signal on pin 5 of Arduino
byte cmd_byte2 = B00010001 ; // Command byte
int initial_value = 100; // Setting up the initial value
void initialize() { // send the command byte of value 100 (initial value)
spi_out(CS_signal, cmd_byte2, initial_value);
}
void spi_out(int CS, byte cmd_byte, byte data_byte){ // we need this function to send command byte and data byte to the chip
digitalWrite (CS, LOW); // to start the transmission, the chip select must be low
spi_transfer(cmd_byte); // invio il COMMAND BYTE
delay(2);
spi_transfer(data_byte); // invio il DATA BYTE
delay(2);
digitalWrite(CS, HIGH); // to stop the transmission, the chip select must be high
}
void spi_transfer(byte working) {
for(int i = 1; i <= 8; i++) { // Set up a loop of 8 iterations (8 bits in a byte)
if (working > 127) {
digitalWrite (MOSI_signal,HIGH) ; // If the MSB is a 1 then set MOSI high
} else {
digitalWrite (MOSI_signal, LOW) ; } // If the MSB is a 0 then set MOSI low
digitalWrite (CLK_signal,HIGH) ; // Pulse the CLK_signal high
working = working << 1 ; // Bit-shift the working byte
digitalWrite(CLK_signal,LOW) ; // Pulse the CLK_signal low
}
}
void setup() {
pinMode (CS_signal, OUTPUT);
pinMode (CLK_signal, OUTPUT);
pinMode (MOSI_signal, OUTPUT);
initialize();
Serial.begin(9600); // setting the serial speed
Serial.println("ready!");
}
void loop() {
// read the input on analog pin 0:
int sensorValue = analogRead(A0);
if(sensorValue <= 200){
// Convert the analog reading (which goes from 0 - 1023) to a voltage (0 - 5V):
float voltage = sensorValue * (5.0 / 1023.0);
// print out the value you read:
Serial.println(voltage);
int i = sensorValue;{
spi_out(CS_signal, cmd_byte2, i);
Serial.println(i);
}
}
}