Introduction; Summary Of Major Features - Motorola MVME172 Programmer's Reference Manual

Introduction

This chapter describes the VMEchip2 ASIC, local bus to VMEbus
interface chip.
The VMEchip2 interfaces the local bus to the VMEbus. In addition to the
VMEbus defined functions, the VMEchip2 includes a local bus to
VMEbus DMA controller, VME board support features, and Global
Control and Status Registers (GCSR) for interprocessor communications.

Summary of Major Features

Local Bus to VMEbus Interface:
– Programmable local bus map decoder.
– Programmable short, standard, and extended VMEbus
addressing.
– Programmable AM codes.
– Programmable 16-bit and 32-bit VMEbus data width.
– Software-enabled write posting mode.
– Write post buffer (one cache line or one four-byte).
– Automatically performs dynamic bus sizing for VMEbus cycles.
– Software-configured VMEbus access timers.
– Local bus to VMEbus Requester:
Software-enabled fair request mode;
Software-configured release modes:
Release-When-Done (RWD), and
Release-On-Request (ROR); and
Software-configured BR0*-BR3* request levels.
2VMEchip2
2
2-1