[SOLVED] MCP23017 I2C I/O Expander Input Reading Problem

[Jestin_cubetech]

MCP23017 Input Reading Problem

MCP23017 I2C I/O Expander Input Reading Problem.

write PORTA  //it works fine 

i2c_waitForIdle();
i2c_start(); 
i2c_write(MCP_WRITE); // Opcode write mode   MCP_WRITE=0x40
i2c_write(IODIRA); // set port A as outputs              IODIRA =  0x0     
i2c_write(0x0);       //set port is output    
i2c_stop();

i2c_waitForIdle();
i2c_start(); 
i2c_write(MCP_WRITE); // Opcode write mode   MCP_WRITE=0x40
i2c_write(GPIOA); // set port A as outputs              GPIOA =  0x12     
i2c_write(0x55);       //set output   0x55 
i2c_stop();


              //Problem is Here!  PORTA Reading is not working. 
---------------------------------------------------------------------------------------------

i2c_waitForIdle();
i2c_start(); 
i2c_write(MCP_WRITE); // Opcode write mode   MCP_WRITE=0x40
i2c_write(IODIRA); // set port A as outputs              IODIRA =  0x0     
i2c_write(0xff);       //set port is input    
i2c_stop();

i2c_waitForIdle();
i2c_start();
i2c_write(MCP_WRITE);
i2c_repStart();
i2c_write(MCP_READ); // Opcode read mode
i2c_write(GPIOA);
value=i2c_read(1);        //ACK 
i2c_stop();  
return value;

data output



input reading

 

[Jestin_cubetech]

Re: MCP23017 Input Reading Problem

___________Problem solved !__________






Read Sequence

i2c_waitForIdle();
i2c_start();
i2c_write(MCP_WRITE);
i2c_write(reg); 
i2c_repStart();
i2c_write(MCP_READ); // Opcode read mode
value=i2c_read(0);  //ACK 
i2c_stop();   
return value;

 

[Mazen21]

Re: MCP23017 Input Reading Problem

___________Problem solved !__________


View attachment 76745



Read Sequence

i2c_waitForIdle();
i2c_start();
i2c_write(MCP_WRITE);
i2c_write(reg); 
i2c_repStart();
i2c_write(MCP_READ); // Opcode read mode
value=i2c_read(0);  //ACK 
i2c_stop();   
return value;

Hi,
I'm having problem with reading continuously from the MCP using I2C, do you have any suggestions?

 

[Jestin_cubetech]

use interrupt option it helps to reduce the unwanted read.