Why is the Data Bus Order Swapped Between FX and SX2 In Command Mode While Sending Data?

Question: Why is the data bus order swapped between FX and SX2 in command mode while sending data?

 

Answer:


In the example code the bytes received on the SX2 data bus FD[0..15] are shifted by 8 bits. This is because the order in which data is received in 16-bit mode is swapped in the FX. Here is how the SX2 board sitting on the FX provided in the devopment kit are connected.

SX2 FX
FD[8..15] (LSB)
FD[0..07] (MSB)

Please refer to the xmaster example provided in the development kit for more information on the hardware interface (C:\Cypress\USB\Examples\Sx2\xmaster).