Motorola MVME1X7P - Manual (Page 91)

2-1
2
2 VMEchip2
Introduction
This chapter describes the VMEchip2 ASIC, the local-bus/VMEbus
interface chip.
The VMEchip2 interfaces the local bus to the VMEbus. In addition to its
VMEbus-defined functions, the VMEchip2 includes a local-bus-to-
VMEbus DMA controller, VME board support features, and Global
Control and Status Registers (GCSRs) for interprocessor communications.
The following table summarizes the characteristics of the VMEchip2
ASIC.
Table 2-1. Features of the VMEchip2 ASIC
Function 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 with:
– Software-enabled fair request mode
– Software-configured release modes:
Release-When-Done (RWD) and
Release-On-Request (ROR)
– Software-configured BR0
∗
-BR3
∗
request levels