I2C Non-standard Read Command

[giogonza]

Hi all!

I've been working with the USB-8451 for a while and now I'm trying to communicate with an Atmel AT88SCXX memory but I'm having a hard time. Maybe someone had already a similar problem and can help me out. This is my situation: I'm developing a program to communicate with the AT88SCXX memory (crypto memory) by using the I2C interface of a USB-8451. Unfortunately, the Read command for this memory does not comply with the I2C Philips standard because it requires a "0" bit in the LSB of the first byte so when I try to use any of the read commands provided for the NI-8451 I got an error message. Somehow I need to develop a customized command sequence with the output similar to the one shown in the picture attached and my software should capture the returned bytes.

This is:  

start--Dev Address-LSB=0--- Word Addr1 ---Word Addr2 ---Parameter N---- Returned byte1------ Returned byte1-----........Returned byteN ----Stop 

(after every byte sent or received memory returns and acknoledge except for the last returned byte) 

Where Parameter N is the number of bytes I want to read, Word Addr1 and 2 depend on the user zone I want to access. I’m kind of stuck with this read command so any help will be appreciated. I'm using Labwindows/CVI 8.2. 

Thanks, 

 

[Chris G in AE]

Duplicate post.  Please see the CAN & DeviceNet forum post for the current thread.