X9241A - Digital Potentiometer
From Combustory
Welcome to Combustory
Any questions or comments:
- Send them to - combustor@combustory.com
|
Warning
This page is in progress and none of the code can be considered good or complete. I am just using this as an alternate storage of the code for right now.
Summary
Example of Method
I2C
There are basically only two functions that I am after right now which are both three byte instructions:
- Read WCR(Wiper Control Register) for the four potentiometers 0-3 (So far this is failing miserably)
- Send 1st byte - Address (my circuit - 01011010 or 0x2D)(binary - 0101 A3 A2 A1 A0) A values are actual pins set to high or low for an address.
- Send 2nd byte - Instruction (binary - 1001 (1/0)(1/0) 00) - The two bits are used to choose the potentiometer
- Read WCR requested Byte
- Write WCR for the four potentiometers 0-3 (This works)
- Send 1st byte - Address (my circuit - 01011010 or 0x2D)(binary - 0101 A3 A2 A1 A0) A values are actual pins set to high or low for an address.
- Send 2nd byte - Instruction (binary - 1010 (1/0)(1/0) 00) - The two bits are used to choose the potentiometer
- Send WCR Byte - Potentiometer value (binary - 00 D5 D4 D3 D2 D1 D0) - D values are the 0-63 potentiometer positions
Sample Code
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xa0); //Instruction to write WCR-00
Wire.send(0x20); //Send a D value of 32
Wire.endTransmission();
DS1307 - Real Time Clock
The code for this very useful chip came from the [Glacial Wanderer]
x9241A_Digital_Potentiometer_v.01 code
/*
* x9241A Digital Potentiometer v.01
* by <http://www.combustory.com> John Vaughters
*
* This Program illustrates the use of I2C to set up the x9241A Digital Potentiometer by setting and transferring the registers.
* I attempted to read the register data through I2C, but was unable to get it to work.
* Since the reading part was not so important to me I stopped trying.
* To set the registers up and transfer them to the Wiper registers met my goals and that is where I stopped.
*
* The x9142A has four Digital Pots and each pot has four static registers and one dynamic register the Wiper Control Register (WCR).
* Therefore, there are 16 total bytes of storage and four WCR's.
* This Program has the following commands:
* S - Set the 16 registers. Each pot has four registers and this command will set each register group with the same value. So register 00 for each pot will
* be the same value for each pot, and the same for register 01 through 11.
* G(0-3) - Global Transfer of Registers to the WCR's. This command will bulk load the values stored in registers into the WCR's.
* For example, a G0 will load the 00 register for each pot into the WCR in one command. A G1 loads the 01 register for each pot, etc.
* (0-3)(0-3) - This set of commands transfers a single register into a single WCR. The digits are arranged like this (WCR)(Reg).
* For example, a 00 command will load register 00 into WCR 00 or a 13 command will load register 11 into WCR 01, etc.
* W(0-3) - This command writes directly to the WCR. I have created four values that are just random, but the command shows how to write directly to the WCR for each pot.
* For example, a W0 command will write a value of decimal 16. These commands are just for example purposes.
*
* Command Note: If you enter a command that is not recognized, then it is ignored and nothing happens and nothing is printed.
*/
#include "Wire.h"
#define X9241_I2C_ADDRESS 0x2D
// Global Variables
long command;
void setup() {
Wire.begin();
Serial.begin(57600);
}
void loop() {
if (Serial.available()) { // Look for char in serial que and process if found
command = Serial.read();
if (command == 83) { //If command = "S" Set Register Data
// This sets the four registers of each Digital Pot
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xc0); // This is the set register command c and the 16 registers are 0-f
Wire.send(0x0a); // This line is the value to set the register: 0-63 is a valid setting
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xc1);
Wire.send(0x14);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xc2);
Wire.send(0x20);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xc3);
Wire.send(0x3c);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xc4);
Wire.send(0x0a);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xc5);
Wire.send(0x14);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xc6);
Wire.send(0x20);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xc7);
Wire.send(0x3c);
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xc8);
Wire.send(0x0a);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xc9);
Wire.send(0x14);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xca);
Wire.send(0x20);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xcb);
Wire.send(0x3c);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xcc);
Wire.send(0x0a);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xcd);
Wire.send(0x14);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xce);
Wire.send(0x20);
Wire.endTransmission();
delay(100);
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xcf);
Wire.send(0x3c);
Serial.println("cmd: S");
}
else if (command == 71) { //If command = "G" Transfer Global Register Data
delay(100);
if (Serial.available()) {
command = Serial.read();
if (command == 48) { // If command = "0"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0x10); // Global Load WCR's with Reg-00
Wire.endTransmission();
Serial.println("cmd: G0");
}
else if (command == 49) { // If command = "1"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0x11); // Global Load WCR's with Reg-01
Wire.endTransmission();
Serial.println("cmd: G1");
}
else if (command == 50) { // If command = "2"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0x12); // Global Load WCR's with Reg-10
Wire.endTransmission();
Serial.println("cmd: G2");
}
else if (command == 51) { // If command = "3"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0x13); // Global Load WCR's with Reg-11
Wire.endTransmission();
Serial.println("cmd: G3");
}
}
}
else if (command == 48) { //If command = "0" Transfer Register-00 Data to WCR 0-3
delay(100);
if (Serial.available()) {
command = Serial.read();
if (command == 48) { // If command = "0"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xd0); // Load WCR-00 with Reg-00
Wire.endTransmission();
Serial.println("cmd: 00");
}
else if (command == 49) { // If command = "1"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xd1); // Load WCR-00 with Reg-01
Wire.endTransmission();
Serial.println("cmd: 01");
}
else if (command == 50) { // If command = "2"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xd2); // Load WCR-00 with Reg-10
Wire.endTransmission();
Serial.println("cmd: 02");
}
else if (command == 51) { // If command = "3"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xd3); // Load WCR-00 with Reg-11
Wire.endTransmission();
Serial.println("cmd: 03");
}
}
}
else if (command == 49) { //If command = "1" Transfer Register-01 Data to WCR 0-3
delay(100);
if (Serial.available()) {
command = Serial.read();
if (command == 48) { // If command = "0"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xd4); // Load WCR-01 with Reg-00
Wire.endTransmission();
Serial.println("cmd: 10");
}
else if (command == 49) { // If command = "1"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xd5); // Load WCR-01 with Reg-01
Wire.endTransmission();
Serial.println("cmd: 11");
}
else if (command == 50) { // If command = "2"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xd6); // Load WCR-01 with Reg-10
Wire.endTransmission();
Serial.println("cmd: 12");
}
else if (command == 51) { // If command = "3"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xd7); // Load WCR-01 with Reg-11
Wire.endTransmission();
Serial.println("cmd: 13");
}
}
}
else if (command == 50) { //If command = "2" Transfer Register-10 Data to WCR 0-3
if (Serial.available()) {
command = Serial.read();
if (command == 48) { // If command = "0"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xd8); // Load WCR-10 with Reg-00
Wire.endTransmission();
Serial.println("cmd: 20");
}
else if (command == 49) { // If command = "1"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xd9); // Load WCR-10 with Reg-01
Wire.endTransmission();
Serial.println("cmd: 21");
}
else if (command == 50) { // If command = "2"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xda); // Load WCR-10 with Reg-10
Wire.endTransmission();
Serial.println("cmd: 22");
}
else if (command == 51) { // If command = "3"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xdb); // Load WCR-10 with Reg-11
Wire.endTransmission();
Serial.println("cmd: 23");
}
}
}
else if (command == 51) { //If command = "3" Transfer Register-11 Data to WCR 0-3
delay(100);
if (Serial.available()) {
command = Serial.read();
if (command == 48) { // If command = "0"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xdc); // Load WCR-11 with Reg-00
Wire.endTransmission();
Serial.println("cmd: 30");
}
else if (command == 49) { // If command = "1"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xdd); // Load WCR-11 with Reg-01
Wire.endTransmission();
Serial.println("cmd: 31");
}
else if (command == 50) { // If command = "2"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xde); // Load WCR-11 with Reg-10
Wire.endTransmission();
Serial.println("cmd: 32");
}
else if (command == 51) { // If command = "3"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xdf); // Load WCR-11 with Reg-11
Wire.endTransmission();
Serial.println("cmd: 33");
}
}
}
else if (command == 87) { //If command = "W" write directly to WCR 0-3
delay(100);
if (Serial.available()) {
command = Serial.read();
if (command == 48) { // If command = "0"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xa0); //Instruction to write WCR-00
Wire.send(0x10); //Send a D value of 16
Wire.endTransmission();
Serial.println("cmd: W0");
}
else if (command == 49) { // If command = "1"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xa4); //Instruction to write WCR-01
Wire.send(0x20); //Send a D value of 32
Wire.endTransmission();
Serial.println("cmd: W1");
}
else if (command == 50) { // If command = "2"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xa8); //Instruction to write WCR-10
Wire.send(0x2a); //Send a D value of 26
Wire.endTransmission();
Serial.println("cmd: W2");
}
else if (command == 51) { // If command = "3"
Wire.beginTransmission(X9241_I2C_ADDRESS);
Wire.send(0xac); //Instruction to write WCR-11
Wire.send(0x30); //Send a D value of 48
Wire.endTransmission();
Serial.println("cmd: W3");
}
}
}
}
}
//*****************************************************The End***********************
A/C_Control_v.01 User Guide
Commands
Troubleshooting
Summary
When Troubleshooting a multi-functional issue, it is best practice to break down the issue into pieces and test each piece as a separate system. However, we will first run through a quick test to see if we can find any obvious issues first.
