I2C addressing

[ssultana]

Hi,I was trying to use MAX518 (DAC) and the write address for MAX518 is 0x58. But it looks like my master I2C cannot communicate with the DAC.Can anybody suggest me what can be issue here?

[lgitlitz]

Take a look at the following topic for debugging communication with I2C:
http://forum.embeddedethernet.com/viewt ... ?f=5&t=982
You should scan through all the addresses on a NetBurner dev board. This will confirm the bus is okay since you will see the RTC respond to its address, hopefully you will also see your added device respond to its addresses.

-Larry

[ssultana]

Thanks for quick response. I figured it out that the address fro MAX518 was not the correct one as mentioned in the data sheet.I had to devide it by 2 and it worked fine.

[pbreed]

RANT!

The I2C spec says addresses are 7 bits with a Read/Write flag.

Yet MANY MANY MANY data sheets publish an 8 bit address with different addresses for read/write.

On a device like a DAC that might not have a datasheet read address you have no way to tell if the data sheet is wrong.

If the data sheet has BOTH a read and write address it's an error and the address you really want is the write address /2

So if I2C does not work, first try to use the data sheet write address /2.

/RANT!

[ahbushnell]

Do you have an AP note or example code for I2C?

Thanks