carl lin

SPI and MSB

Discussion created by carl lin on Apr 10, 2012

hi, 

 

    currently we are using code warrior 5.9.0 to develop MCU  S9S12XET256MAL for our new product. We need to use SPI to communicate with another device.

 

   to test the SPI function on this MCU, I hooked up our own two internal developed boards with exact MCU and everything together. the basic function is that I press one button and the master board transmits one value, which increments with every press, to the slave board and display on its LED.

 

    I have no problem using LSB for transmission between the master and the slave. However, when I use MSB, it seem that slave is having problem on fifth press of the button on the master. the LED on slave board stuck on 4. I press two more times and the LED displays 0xc0. I have checked the generated code and my write code and I don't see anything wrong.

 

any help would be greatly appreciated, thanks. 

 

Carl  

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