Description
The ST-BUS Parallel Access Circuit (STPA) provides a simple interface between Mitel’s ST-BUS and
parallel system environments.

FEATUREs
• High speed parallel access to the serial ST-BUS
• Parallel bus optimized for 68000µP (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