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four decoder at location D4 is the setting of the board select
flip/flop, a section of the 74LS74 at location D2, which is used
to select that board which puts data on the DATA IN (DI) bus
when a data input FE command is issued so that the protect status
can be read by the microprocessor.
carry the status of the write protect flip/flops for memory
blocks 0, 1, 2 and 3.
the DI bus through the 8T97 at location D3.
bits of the DATA IN bus, DX 4, D r 5, DT 6 , and DI 7
board address as.set by the jumpers at location C5.
There is a flip/flop, a section of a 74LS74 at location D2, that
becomes set if a write operation is attempted into a block of
memory that is write protected.
whose open collector output can Be jumper connected to the
INTERRUPT REQUEST CPINTl bus line pin 73, or to one of the
vectored interrupt lines on Bus pins 4 through 11.
notifies the user that a write has Been attempted in a protected
block of memory .
interrupt routine.
4
6
This status Information is gated onto
This flip/flop drives a transistor
The, user may handle this interrupt with an
DI 0, DI 1, DX 2, and DI 3
The regaining four
This interrupt
carry the
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