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3.4 OPTION MODULES
Optional modules can be added to the Rainbow 100 computer to increase memory size, expand the
communications functions, and provide a c()lor/graphics capability. These optional modules are mounted
on the system module and plug directly into cannectors provided for them. A brief description .of the
available options is given in the fallowing paragraphs. Additianal information far these options can be
obtained from the following installation guides:
Title
Rainbow™ Memory Extension Option Installation Guide
Rainbow™ 100 Extended Communication Option Installation Guide
Rainbow™ Color/Graphics Option Installation Guide
3.4.1
Memory Extension Option
Document Number
EK-PCMXE-IN
EK-PCEXC-IN
EK-PCCOL-IN
The me mary extensian option for the Rainbaw 100 camputer allaws the user to upgrade the system
memory with an additianal 64K bytes .or I92K bytes of dynamic ranQQm-access memary (DRAM) that
can be written into as well as read. Two versians of the memory extension option are available: a 64K byte
option (part number PCIXX-AA) and a I92K byte optian (part number PCIXX-AB). The memory
option is installed in the J6 connector on the system madule. These .options added ta the existing 64K bytes
of DRAM an the system module provide the Rainbow 100 computer with a total system memory of I28K
bytes .or 256K bytes.
Both versions of the memary extension option use the same printed circuit board etch and the same type of
64K
X
1 bit memory chips. The 64K byte version of the option contains nine 64K
X 1
bit chips and the
192K byte version contains twenty-seven 64K
X
1 bit chips arranged as three 64K byte memory stacks.
Eight of the 64K
X
I chips in each stack cantain the 8 bits of the data byte and the ninth contains the
parity bit. The 64K byte version of the option is not user upgradable.
When installed, this added memory is always available ta the 8088 processor and will require wait states
only when the memory cycle and refresh cycle contend for use of the memory.
The memory optian is equipped with a parity generation and parity errar detectian circuit to natify the
8088 processar when a parity error .occurs. If a parity errar .occurs, the memory .option transmits a parity
error signal to the nanmaskable interrupt input .of the 8088. The 8088 then vectars to a ROM parity error
program in the 24K byte ROM that will display an error message an the screen.
3.4.2
Extended Communications Option
The extended communications optian is a majar companent of the Rainbow 100 computer and is plugged
directly into two 40-pin cannectors (J4 and J5) on the system module. The module cantains a dual-channel
multiprotocol serial cantroller (MPSC) and supparting logic. The purpase of the optian is to add a second
communications connector with bit and byte synchronous capability to the Rainbow 100. This option also
provides a separate high-speed communications cannector.
The extended cammunications option performs the fallawing functions:
I.
By means of the 8237 DMA cantroller, transfers data bidirectionally between memary and the
high-speed communications link (MPSC) with minimum processor intervention. The transfer
to/from memary uses the shared 64K byte RAM only and not any installed optional memory.
2.
Provides two complete serial communications cantrollers in a single MPSC package ta:
a.
Convert parallel data (from the pracessor) to serial data, as required by various cammuni-
cations protocols.
3-14
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