MT8920B-1 Datasheet, PDF (1/29 Pages) Mitel Networks Corporation – ISO-CMOS ST-BUS™ FAMILY ST-BUS Parallel Access Circuit

ISO-CMOS ST-BUS™ FAMILY MT8920B
®
ST-BUS Parallel Access Circuit
Features
• High speed parallel access to the serial ST-BUS
• Parallel bus optimized for 68000 µP (mode 1)
• Fast dual-port RAM access (mode 2)
Access time: 120 nsec
• Parallel bus controller (mode 3) - no external
controller required
• Flexible interrupt capabilities - two
independent/programmable interrupt sources
with auto-vectoring
• Selectable 24 and 32 channel operation
• Programmable loop-around modes
• Low power CMOS technology
Applications
• Parallel control/data access to T1/CEPT digital
trunk interfaces
• Digital signal processor interface to ST-BUS
• Computer to Digital PABX link
• Voice store and forward systems
• Interprocessor communications
ISSUE 7
March 1997
Ordering Information
MT8920BE 28 Pin Plastic DIP
MT8920BP 28 Pin Plastic J-Lead
MT8920BS 28 Pin SOIC
-40°C to 85°C
Description
The ST-BUS Parallel Access Circuit (STPA) provides
a simple interface between Mitel’s ST-BUS and
parallel system environments.
D7-D0
A4-A0
CS
DS, OE
R/W, WE
DTACK,
BUSY, DCS
IRQ, 24/32
IACK, MS1
A5, STCH
MMS
Parallel
Port
Interface
Interrupt
Registers
Control
Registers
Tx0
Dual Port Ram
32 X 8
Rx0
Dual Port Ram
32 X 8
Tx1
Dual Port Ram
32 X 8
Parallel-
to-serial
Converter
Serial-to-
Parallel
Converter
Parallel-
to-Serial
Converter
Address
Generator
STo0
STi0
Comp/
MUX
STo1
F0i
C4i
V_SS
V_DD
Figure 1 - Functional Block Diagram
3-3