How are the bytes loaded to the data pins for Express Mode?
The Express Mode is supported by the XC5200, XC4000XLA and Spartan-XL only.
The Express configuration mode downloads data at a frequency of a byte per configuration clock. The order this byte is downloaded is the same as it would be downloaded in Peripheral Configuration Mode. The MSB of the bit file goes to D0, and the LSB of each of the bit files goes to D7.
The First two bytes of data in the 5200 bit file are:
The Fill Byte: 11111111
The Preamble: 11110010
Therefore the first byte of data would be:
D0=1 , D1=1, D2=1, D3=1, D4=1, D5=1, D6=1, D7=1
And the second byte of data would be:
D0=1 , D1=1, D2=1, D3=1, D4=0, D5=0, D6=1, D7=0