Philips SPENDEX 40 Maintenance Manual page 25

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S P E N D E X 4 0 U A 8 2 5 1 / 0 0 A N D / O l L I M I T E D M A I N T E N A N C E M A N U A L
4 . 8 C o n t r o l l e r b o a r d
4 . 8 . 1 C o m s e c c o n t r o l l e r
The comsec controller takes care of the central control of the
equipment and exchanges via the comsec bus system data and control
signals with the various circuits.
H 4 . 8 . 2 P r o g r a m m e m o r y 1
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Program memory 1 (M EPROM, 32,768 x 8 bit) contains part of the
firmware.
4 . 8 . 3 D a t a m e m o r y r e d
The data memory red (2048 x 8 bit) is the working memory which is
exclusively used by the comsec controller for crypto operations.
4 . 8 . 4 D a t a m e m o r y b l a c k
The data memory black (2048 x 8 bit) is the working memory which is
used by the comsec controller for non-crypto operations. The memory
contains temporary auxiliary information, like flags, pointers and
the stack.
4 . 8 . 5 A d d r e s s d e c o d e r
The address decoder takes care of the addressing of the various 1/0-
and memory locations within the apparatus.
4 . 8 . 6 I n t e r r u p t c i r c u i t
The interrupt circuit processes all interrupt signals of the various
circuits and generates from them the interrupt commands TRAP,
RST 7.5, RST 6.5 and RST 5.5 for the comsec controller.
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