Reading from GPIO expander

2007-11-29T09:04:39Z

Hi all,

I am using MPC5200B CPU. I am using both the I2C buses of the CPU.

I have connected a PCA9546A 4channel I2C MUX in the one bus.
Through the first channel of the MUX I have connected GPIO expander PCF8754.

I am able to write into the GPIO expander data register.
Both making the register values high or low is possible by means “imm” command.

When I try to read the GPIO expander data register by means of “imd” command I am not getting the value that was written earlier, instead of that I am getting “00” ( GPIO expander register also getting cleared).

I don’t know what may be the issue.
Please help me how I can read the value that was written previously.

Regards,
Yasotha Balan R

Devantech USB-I2C R286-USB-I2C Board

2007-02-26T11:00:18Z

Hello,

I just purchased Devantech USB-I2C R286-USB-I2C board for my project. The Devantech USB-I2C module is a low cost USB to I2C module, with a simple command set, and interfacing to any I2C device. I'm trying to set the I2C interface between my I2C board and R286-USB-I2C?

My question is If anybody tried to develop the user interface for this board already? My goal to use this USB to I2C adapter in order to read of 24C208 (It has two completely separate I2C busses, which can both access the EEPROM simultaneously). I need a help with that.

Thanks in advanced,

Michael

Nabble - I2C Bus

Reading from GPIO expander

Devantech USB-I2C R286-USB-I2C Board