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User Manual for Microboard Computer Development System CDP18S693 & CDP18S694
Table XI—ROM Type Selection Links
Link
ROM Type
LK4
Pins CDP1834
2708f
2758
2716*
1:18
X
O P E N
S H O R T E D
S H O R T E D
2:17
X
S H O R T E D
O P E N
O P E N
3:16
S H O R T E D
S H O R T E D
S H O R T E D
O P E N
4:15
O P E N
O P E N
O P E N
S H O R T E D
5:14
O P E N
O P E N
O P E N
S H O R T E D
6:13
S H O R T E D
S H O R T E D
S H O R T E D
O P E N
7:12
X
S H O R T E D
O P E N
O P E N
8:11
X
O P E N
O P E N
S H O R T E D
9:10
X
O P E N
S H O R T E D
O P E N
X=dorVt care;
*L in kLK4 is prewired to accept 2716.
tUse of 2708’s requires extra voltages of12voltsand5volts on
pins 20 and 11, respectively, of the Universal Backplane
Connector P1
To avoid having floating inputs to the gates, both
links LK10 and LK22 should always have two
jumpers. For example, if sockets XU26 and XU27 are
unused, LK22 may be jumpered the same as LK10.
Otherwise, spurious chip selects may be generated,
turning on the three-state data buffers and causing
interference with normal processing.
For 1-kilobyte ROM’s such as the CDP1834, 2708,
or 2758, links LK10 and LK22 should bejum pered
identically in accordance with Table XI. Then, the
ROM ’s should be installed in sockets XU25, XU27,
XU24, and XU26, in that order, starting with the
lowest-address ROM.
For 2-kilobyte ROM’s (2716), links LK10and LK22
should bejumpered independently in accordance with
Table X for the required two 4-kilobyte blocks.Then,
socket XU25 is the low 2 kilobytes and socket XU24 is
the high 2 kilobytes of the 4-kilobyte block as set in
LK10. Similarly, socket XU2 is the low 2 kilobytes and
socket XU26 is the high 2 kilobytes of the 4-kilobyte
block set in LK22.
One-kilobyte ROM type CDP1834 is the only one
that may be used in combination with two-kilobyte
ROM’s type 2716. If all links are set up for the 2-
kilobyte ROM’s as shown in Table X for LK4, and
LK10 and LK22 are set up for different 4-kilobyte
blocks, then a 1-kilobyte ROM in socket XU25 will
occupy the two lower 1-kilobyte segments of the 4-
kilobyte block. In other words, its 1 kilobyte will
“wrap” through the lower 2 kilobytes of the 4-kilobyte
block. If it is in socket XU24, it will wrap through the
upper 2 kilobytes of the 4-kilobyte block. A 2-kilobyte
ROM may be placed in either socket XU24 or socket
XU25 while the other is occupied by a 1-kilobyte
ROM. Socket XU27 (low 2 kilobytes) and socket
XU26 (high 2 kilobytes) may be used in the same
manner.
and CDP18S694 is 65,536 bytes. Because of the
M icroboard Universal Bus and Backplane, the
memory provided with the System can be readily
expanded by the addition of RCA M icroboard
Memory Modules or by the use of custom designed
memories. A system memory map is given in Fig. 12.
ADDRESS
FREE TO USER
C D P I8 S 6 5 2 SOCKETS
8 A S IC 3
R O M 'S
-E D IT O R /A S S E
________________i
M B LER R O M 'S -
[________________
I - KILOBYTE RAM
U T 6 2 MONITOR
FREE FOR USER
EXPANSION
RAM ON C D P I8 S 6 0 I BOARD
FOOO - FFFF
E O O O -E F F F
D O O O -D F F F
C O O O -C F F F
B O O O -B F F F
A 0 0 0 - A 8 0 0
9 0 0 0 - 9 F F F
8 C O O -8 F F F
8 0 0 0 - 8 7FF
7 0 0 0 - 7 F F F
6 0 0 0 - 6 F F F
5 0 0 0 - 5FFF
4 0 0 0 - 4 F F F
3 0 0 0 - 3 F F F
2 0 0 0 - 2FFF
1 0 0 0 - I FFF
O O O O -O F F F
SPACE
( KILOBYTES)
4
4
4
4
4
2
4
1
2
4
4
4
4
4
4
4
4
92C S- 34211
Fig. 12—Memory map forM C D S CDP18S693 and
CDP18S694.
RCA Memory Modules
The RCA Microboard Memory Modules available
to expand the R A M /R O M capability of the
CDPl8S693 and CDPl8S694 include the following:
4-Kilobyte RAM CDP18S620
4-Kilobyte Battery-Backup RAM CDPl8S624
8-Kilobyte RAM CDP18S623
8-Kilobyte Battery-Backup RAM CDP18S622
l6-Kilobyte RAM CDP18S62l
32-Kilobyte RAM CDP18S629
4-Kilobyte EPROM CDPl8S627
8/ l6/32-Kilobyte ROM /PROM CDP18S625
32/64-Kilobyte EPR O M /RO M / RAM CDP18S626
Each of these Microboard modules has decoders with
link options that allow the memory to be user-assigned
within the 64-kilobyte address range.
Custom Memory Modules
Memory Expansion
The addressable memory range of the CDP18S693
Users who wish to design and construct their own
memory systems can do so by carefully observing the
physical and electronic constraints of the Microboard