mh2080 Music Semiconductors, Inc., mh2080 Datasheet - Page 5

• Manufacturer Part Number: mh2080
• Description: Hla Packaged Asynchronous Data Recognition And Recall Processor
• Manufacturer: Music Semiconductors, Inc.

/AV (Address Valid, Input)
When Hardware control is selected, the /AV input
determines whether the AC bus carries address or control
information. When /AV is LOW, the AC12-0 bus conveys
a memory address; when /AV is HIGH, the AC bus
conveys control information. The state of the /AV line is
registered by the falling edge of /E. When software control
is selected, the /AV line distinguishes between instructions
and data on the DQ31-0 lines; when /AV is LOW, data is
present on the DQ31-0 lines; when /AV HIGH, either an
instruction is presented to the DQ8-0 lines (Write cycle,
/W is low) or the status register value is present on the
DQ31-0 lines (Read Cycle, /W is high).
/VB
Input/Output)
During accesses over the DQ31-0 lines, the /VB line
conveys validity information to and from the MH2080.
During a Write cycle (/W=LOW), when /VB is LOW the
addressed location is set valid; when /VB is HIGH it is set
empty. During a Read cycle (/W=HIGH), the validity of
the addressed location is read on the /VB line. During a
Write cycle, the state of the /VB line is registered by the
falling edge of /E.
/MF (Match Flag, Output)
The /MF output indicates whether a valid match has
occurred during the previous Comparison cycle. If the
/MF output is HIGH at the end of a Comparison cycle,
then no match occurred; if it is LOW then either a match
occurred within the device, or the /MI input is LOW,
conditioned by the /MF output from a higher-priority
device in the system. The state of the /MF line will not
change until after the rising edge of /E during the
Comparison cycle. Note that /MF indicates the results of
the most recent Comparison cycle; it will not change when
the PA:AA bus carry an address other than the Match
address.
/MI (Match Input, Input)
The /MI input receives match information from the next
higher-priority MH2080 in a vertically cascaded system to
provide system-level prioritization. When the /MI input is
HIGH, the /MF output will only go LOW if there is a
match during a Comparison cycle; when the /MI input is
LOW, the /MF output will go LOW. The /MF output from
one device is connected to the /MI input of the next
lower-priority device. The /MI pin of the highest-priority
device must be tied HIGH.
Rev. 1.1a
(Validity
Bit,
Three-state,
Common
5
/FF (Full Flag, Output)
The /FF output indicates when all the memory locations
have their Validity bits set valid (LOW). When there is at
least one location with its Validity bit set HIGH, the /FF
output will be HIGH; when all locations have their
Validity bits set LOW, and the /FI input is LOW, the /FF
output will be LOW. If the /FI input is HIGH, the /FF
output will be HIGH. The state of the /FF line will not
change until after the rising edge of /E during a Write
cycle.
/FI (Full Input, Input)
The /FI input receives full information from the next
higher-priority MH2080 in a vertically cascaded system to
provide system-level full information. When the /FI input
is LOW the /FF output will be HIGH if there is at least one
location whose Validity bit is set invalid; when all
locations have their Validity bits set valid, the /FF output
goes LOW. When the /FI input is HIGH, the /FF output
will remain HIGH. The /FF output from one device is
connected to the /FI input of the next lower-priority device
to give system-full indication. The /FI pin of the
highest-priority device must be tied LOW.
/MM (Multiple Match, Open Drain Output)
The /MM line indicates that there is a multiple match
within the system. When the /MI input is HIGH, the /MM
line is pulled LOW if there are at least two matches within
the MH2080 as a result of the previous Comparison cycle;
when there are less than two matches, the /MM line floats
HIGH. When the /MI input is LOW, the /MM line is
pulled LOW if there are one or more matches within the
MH2080 as a result of the previous Comparison cycle;
when there are no matches, the /MM line floats HIGH.
The /MM lines have open-drain outputs, so all /MM lines
within the system are connected together to give
system-level multiple match indication. The state of the
/MM line will not change until after the rising edge of /E
during a Comparison cycle.
/RESET
The /RESET input is used to reset the MH2080 to a known
state. When the /RESET line is pulled LOW it causes the
MH2080 to enter its reset state. After power is applied to
the MH2080, the /RESET line must be held LOW for a
time equal to or greater than the minimum RESET pulse
width before the device can operate correctly. This pin is
internally pulled up.