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Arbiter output

The uses a round robin priority scheme with Master0 having the default priority. Thispriority scheme assures that each master equally has its turn at acquiring and completing an

AHB bus transaction. Each inactive master is locked out (HLOCK) while the active master has

access to the bus to prevent contention. The steers all the AHB HWDATA, HADDR,HTRANS, HWRITE, HSIZE and HBURST signaling from each master to the AHB system bus.

The is delivered as a three master arbiter but can easily be configured to allow up to sixteen

AHB bus masters.

Data transfer output

Every transfer can be classified into one of four different types, as indicated by theHTRANS[1:0] signals as shown Indicates that no data transfer is required. The IDLE transfer

type is used when a bus master is granted the bus, but does not wish to perform a data transfer.

The BUSY transfer type allows bus masters to insert IDLE cycles in the middle of bursts of

transfers. Indicates the first transfer of a burst or a single transfer. The address and controlsignals are unrelated to the previous transfer.

Control generator

As well as the transfer type and burst type each transfer will have a number of controlsignals that provide additional information about the transfer. These control signals have exactly

the same timing as the address bus. However, they must remain constant throughout a burst of

transfers. When HWRITE is HIGH, this signal indicates a write transfer and the master will

broadcast data on the write data bus, HWDATA[31:0]. When LOW a read transfer will beperformed and the slave must generate the data on the read data bus HRDATA[31:0].

Master output

An AHB bus master has the most complex bus interface in an AMBA system. Typically

an AMBA system designer would use predesigned bus masters and therefore would not

need to be concerned with the detail of the bus master interface.

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SYNTHESIS REPORT

The standard procedure for hardware design consists of describing circuit in ahardware description language at logic level followed by extensive verification and

logic-synthesis. However, this process consumes significant time and needs a lot of

effort. An alternative is to use formal specification language as a high-level hardware

description language and synthesize hardware from formal specification. Bloem

et.al. gave formal specifications and synthesize the AMBA AHB Arbiter. Our

contributions are as follows:(1) We present more complete and compact formal

specifications for the AMBA AHB Arbiter, and obtain significant (order of magnitude)

improvement in synthesis results (both with respect to time and the number of gates

of the synthesize circuit); (2) we present formal specification and synthesize to

generate compact circuits for the remaining two components of the AMBA AHBprotocol, namely, the AMBA AHB Master and AMBA AHB Slave; and (3) from the

lessons learnt we present few principles for writing formal specifications for efficient

hardware synthesis. Thus with intelligently written complete formal specifications we

are able to automatically synthesize an important and widely used industrial

protocol.