How do I control LEDs using an MCP23008?
I have tried Searching but they all seem to refer to LCD Displays.
I want to turn all Outputs on & off!
http://files.jeelabs.org/2009/11/DSC_0756.jpg
Thanks in advance
There are two types of this chip the MCP23008 and the MCP23S08, I can't tell which you have.
If it is the MCP23008 then this is the I2C version and is quite easy to drive. Look at the data sheet and see the internal registers. You have to set up the data direction register to be outputs and then write to the output register.
I used the larger MCP23016 in this project:-
http://www.thebox.myzen.co.uk/Hardware/Pendulum.html
This is the same chip only with an A and a B side. That project just uses them for turning on LEDs. Down load the code and take a look what I did.
#include <Wire.h>
void setup() {
Wire.begin(); // initialise the wire library and hardware
Wire.beginTransmission(0x26); // start talking to the device
Wire.send(0x00); // select the IODIR register
Wire.send(0xff); // set register value-all high, sets all pins as outputs on MCP23008
Wire.endTransmission(); // stop talking to the devicevice
}
void loop() {
Wire.beginTransmission(0x26); // start talking to the device
Wire.send(0x09); // select the GPIO register
Wire.send(0xff); // set register value-all high
Wire.endTransmission(); // stop talking to the device
delay(500); // wait for 1/2 a second
Wire.begin(); // initialise the wire library and hardware
Wire.beginTransmission(0x26); // start talking to the device
Wire.send(0x09); // select the GPIO register
Wire.send(0x00); // set register value-all low
Wire.endTransmission(); // stop talking to the device
delay(500); // wait for 1/2 a second
}
Any clues?
Does this work or not work?
What is it supposed to do?
What happens?
From looking at it you need to set up the data direction register in setup and remove the wire begin from the loop.