2.3.1
Clock Mul ti plier Se lect
486DX4 and 5X86 proc es sors ac tu ally run at a mul ti ple of the base os cil la tor fre quency.
The
jumper block at J36 al lows se lec tion of the mul ti plier as shown here :
2.4
PCI Clock Se lect
The PCI bus clock source must be se lected us ing jumper blocks at J14 and J31. The CPUCLK
source may be se lected any time the CPU base fre quency is less than or equal to 33MHz. For any CPU
base fre quency in ex cess of 33MHz the CPUCLK/2 se lec tion must be made.
2.5
Mem ory In stal la tion
The LBC-Plus util izes user instal la ble 72- pin stan dard SIMMs. SIMM mod ules should be a
minimum speed of 70nS and X32 ar chi tec ture is pre ferred as there is no sup port for the par ity bits pro
-
vided by X36 bit mod ules. A sin gle SIMM socket is pro vided which can sup port DRAM sizes from
1MB to 32MB.
In stal la tion is ac com plished with power off by an gling the SIMM mod ule ap proxi mately 30 de -
grees from ver ti cal and in sert ing the fin gers into the con nec tor (It may be nec es sary to re move any de -
vice in stalled in the U27 socket. ). The SIMM mod ule is keyed slightly off- center and can not be in serted
back wards with out ex treme force. Once the fin gers are in the socket, the mod ule is then ro tated to the
ver ti cal un til the re tain ing clips snap into place. Re moval is the re verse pro cess. Pull the re tain ing clips
out ward and the SIMM mod ule, once re leased, should ro tate back to an ap pro pri ate re moval an gle.
991206
OPERATIONS MANUAL LBC-Plus
Page 2 - 3
WinSystems - "The Embedded Systems Authority"
1 o
2 o
3 o
1 o
2 o
3 o
1 o
2 o
3 o
J14
J14
J31
J31
CPUCLK
CPUCLK/2
1 o
2 o
3 o
1 2 3
o o o
J36
1 2 3
o o o
J36
3X
2X - 486
4X - 5X86
