Emulex DCP_link - Manual (Page 22)

2-8 Chapter 2
Control Register 4 Read Option
Set Jumper J1 to enable (J1-3 to J1-4 connected) host read access to Control
Register 4.
Window Group Select
The DCP286i-SBC contains memory that is shared by the host. The host
software can select the size of the window that is shared using jumper J1:5-6.
The factory default setting (J1-5 to J1-6 connected) allows window sizes of
16K, 32K, 64K or 1MB. By removing this jumper, window sizes of 16K,
64K or 128K are made available.
Memory Size
The memory size on the board, 512 kB or 1MB, is selected by jumper
position J1:7-8. The DCP286i-SBC is shipped with 1 MB of Dynamic
RAM. Remove this jumper to select 512 kB of RAM.