MA28155 Datasheet, PDF (10/20 Pages) Dynex Semiconductor – Radiation Hard Programmable Peripheral Interface

MA28155
OPERATING MODE 2
(Strobed Bidirectional Bus I/0)
This functional configuration provides a means for
communicating with a peripheral device or structure on a
single 8-bit bus for both transmitting and receiving data
(bidirectional bus l/O) . Handshaking signals are provided to
maintain proper bus flow discipline in a similar manner to Mode
1, Interrupt generation and enable/disable functions are also
available.
s Used in group A only.
s One 8-bit bidirectional bus port (port A) and 5-bit control
port (port C).
s Both inputs and outputs are latched,
s The 5-bit control port (port C) is used for control and status
of the 8-bit bidirectional bus port (port A).
DSN
RD/WN
OBFN
ACKN
STBN
NOTE:
Any sequence where RD/WN = 0 coincident with DSN low occurs before ACKN and STBN occurs before RD/WN = 1
coincident with DSN is permissable
(INTR = IBF MASK STBN (RD/WN = 1. DSN = 0) + OBFN MASK ACKN (RD/WN = 0. DSN = 0))
Figure 15: Bidirectional Timing Diagram
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