Specifications

Hardware Configuration
2–25
Figure 2-8 Using 28- and 32- pin Devices in 32-pin Sockets
2.11.1 Addressing the Byte-wide Sockets
Use the CPU SETUP program to specify the size and starting address of each socket, and which
socket the BIOS enables upon system initialization. Table 2-20 lists the possible settings for sizes and
address ranges of the byte-wide sockets.
Note
When a byte-wide socket is enabled, the memory address space
it uses is unavailable for other devices, even if no memory
device is installed in the socket. You must disable the byte-wide
sockets in SETUP before you can use the memory space for
other purposes.
Window Address
DISABLE N/A
64K D0000-DFFFFh
64K E0000-EFFFFh
128K D0000-EFFFFh
Table 2-20 Window Size and Address Selection
The size of the device installed in a byte-wide socket is not limited to 128K bytes. Using a page
addressing scheme, devices (or modules) up to 1M bytes can be used. Higher address lines
(A16-A19) are synthesized and can be set by software. A description and examples of byte-wide page
control are provided in Chapter 3.
2.11.2 Direct Program Access
Application software can access the memory devices in S0 and S1 if the program knows about them.
To access a byte-wide socket, you must enable it. You must enable and disable the sockets in your
application program to prevent a conflict. S0 and S1 can not be enabled at the same time.