Little Board™/486e Technical Manual
Installing a Boot PROM
The Little Board/486e CPU can be configured for a boot PROM by installing the boot PROM in byte-wide socket S0.
Installing a Boot PROM in Byte-Wide Socket S0
Install a LAN boot PROM in byte-wide socket S0. The boot PROM code is run at boot time as a BIOS extension.
To install a LAN boot PROM in byte-wide socket S0, follow these guidelines:
1.Either obtain a preprogrammed boot PROM device, or program a PROM or FLASH EPROM with the boot PROM image. Use a 128K byte device, such as a 27C010, if possible.
2.Install the boot PROM device in S0.
3.In SETUP, set socket S0 for 64K bytes at D0000h and select S0 to be enabled at boot time.
Twisted Pair Interface (J7)
The twisted pair interface (10BaseT) appears on connector J7. It is a standard RJ45 telephone-type modular connector, which is the normal connector used with standard twisted-pair cables. Table 2– 33 lists the signals and pin numbers of J7.
Table 2–33. RJ45 Twisted Pair Connector (J7)
J7 Pin | Function |
| |
1 | + Transmit Data |
| |
2 | - Transmit Data |
| |
3 | + Receive Data |
| |
4 | N/C |
| |
5 | N/C |
| |
6 | - Receive Data |
| |
Twisted-Pair Installations
This section discusses the guidelines for twisted-pair installations.
!Connector jack—A standard RJ45-terminated cable can be plugged directly to the female RJ45 connector on the Little Board/486e CPU.
!Connector plug—The RJ45 connector plugs attach to both ends of twisted-pair Ethernet cable lengths. They are used to connect the Little Board/486e CPU to a hub or concentrator.
!Terminators—There are no external termination devices required. Termination is handled automatically by the hub devices.
Twisted-pair Ethernet cable is 22 or 24 gauge copper wire twisted together in pairs. Ethernet twisted-pair uses two pairs (four wires), one for transmitting and one to receive. It is available from
