XDEV command

Number	$F0
Readable	Yes
Writable	Yes
Short Description	Issue 4 only

 * Select Mode
    (R)
      bit 7 = 1 if in select mode
      bits 1:0 indicate currently selected device
        00 = none
        01 = Xilinx DNA
        10 = Xilinx XADC
    (W)
      bit 7 = 1 to enter select mode, 0 to enter selected device mode (no other bits have effect)
      bit 6 = 1 to change selected device
      bits 1:0 selected device
        00 = none
        01 = Xilinx DNA
        10 = Xilinx XADC
  * Xilinx DNA Mode
    (R)
      bit 0 = dna bit (serial stream shifts left)
      the first eight bits read will indicate the length of the following dna bits
    (W)
      bit 7 = 1 to enter select mode (write has no other effect)
      otherwise causes dna string to reload, ready for fresh read
  * Xilinx XADC Mode (Documented in Xilinx Series 7 UG480)
    (R)
      bit 6 = 1 if XADC is busy with conversion (BUSY)
      bit 1 = 1 if XADC conversion completed since last read (EOC, read clears)
      bit 0 = 1 if XADC conversion sequence completed since last read (EOS, read clears)
    (W)
      bit 7 = 1 to enter select mode (write has no other effect)
      bit 6 = 1 to reset XADC (RESET)
      bit 0 = 1 to start conversion (CONVST)

• Re-enter select mode at any time by writing to the register with bit 7 set
• Select a device to communicate with by writing to the register with bits 6 & 7 set
• Exit select mode by writing zero to bit 7; thereafter the particular device is attached to the nextreg