Updating application in EPCS via UART

// 3) If we arrive at this point we have assume that there is valid-looking

// configuration data. Extract its length. If the extracted length is all

// "1", assume that we're looking at erased flash. In this case, we have

// no other recourse than to hang.

//

// The configuration bitstream length is encoded in a particular bit of a

// run of bytes. Total length field is 32 bits, which goes from CB Option

// bits 86..55 corresponding to bit[3] of byte[39] to byte[33] (for the most

// significant 7 bits) followed by the range of bits made up of bit[2] of

// bytes[72..48].

//

// The note about EPCS bit reversal still applies (so we're really looking

// at bits[4] and [5], respectively.

My best guess is to grab a single bit from 32 different bytes to build the 32 bit length value. The first 7 bits are found in bit 4 of byte 33 thru 39. The remaining 25 bits are found in bit 5 of bytes 48 thru 72. Astoundingly complex...

Dan