I/O Board


  2016/4/6 上午 10:40:55        Administrator        General   0 Comments
The rising popularity and proliferation of I2C device demands specialized measuring equipment for analysis. The article will be looking into accelerating R&D by using Logic Analyzers for analyzing I2C protocols, and, coupled with AAEON’s proprietary Hi-Safe Software, checking the read/write operation of I2C devices.

An Introduction to the I2C Protocol
Data transfer with the I2C protocol begins with a START condition(s), followed by a slave address (7-bits long), a data direction bit (R/W#), Acknowledgement (ACK), and concludes at STOP (P).



An introduction to AD5247
The AD5247 is a 128-position I2C Digital Potentiometer by Analog Devices and serves as an IC to control the brightness of a LCD in AAEON designs. Its 128-position characteristic and convenience brought on by I2C control makes it very viable for this application.



GUI of AAEON’s Hi-Safe Software



Select SMBus



With a Logic Analyzer acting as an I2C protocol analyzer and Bus decoder, engineers will get the first hand information on the data’s read/write status, an impossible feat when oscilloscopes is used for measuring such data-rich information. In Hi-Safe, switching to slave address 2E of AD5247, and setting 00 to both Register of data and Byte 0 will reveal the waveform of WRITE 00, as shown below.

 

When data is set to 1A, the waveform of WRITE 1A is revealed, as shown below.
Data byte), ACK, Stop cycle are highlighted in different colors to make them quicker to be identified and easier to read.


From the image, the changes in S (start), Frame 1 (Slave address byte), ACK, Frame 2 (Register of data), ACK, Frame 3 (Data byte), ACK, Stop cycle are highlighted in different colors to make them quicker to be identified and easier to read.
 
Meanwhile, the operational status of I2C cycle can be determined by measuring the voltage variations at the output of the AD5247.
 
By using the convenient Hi-Safe, the accuracy of the software engineer’s code to the hardware’s circuitry can be determined immediately, greatly minimizing the debugging time needed during development. Not only that, the status of each functions can be known with more precision when a hardware revision is due, shortening the time to market.



 





 
0 Comments
Post Reply