Library for writing to the FPGA CRAM chip.
Work In Progress: It is implemented but needs to be debugged.
Reset the iCE40 and set it to CRAM configuration mode and prepare the incoming SPI transfer.
buf- pointer to bitstream data to flush to the iCE40
len- size of that buffer
Send the bitstream to the iCE40 CRAM, which configures the FPGA circuitry.
Terminate the SPI transaction and prepare the FPGA to start, waiting until it finishes booting.
true if the FPGA configuration succeeded or
false if it timed out.