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Motorola Functional Description 3-1

Chapter 3

Functional Description

The application development system (ADS) user interacts with the target DSP through

two subsystem components, the host computer interface and the command converter

controller. The host computer interface consists of a program written in the C language

that interacts with a host computer bus interface card. The command converter consists of

a program written in DSP56002 assembly language which interacts with the host

computer bus interface card and the target JTAG/OnCE port.

It should be noted that older versions of Motorola DSP products use the OnCE port

protocol, while newer versions of Motorola DSP products use the IEEE JTAG 4-wire

protocol to interact with their OnCE port. New versions of the command converter support

both JTAG and OnCE protocols.

Commands entered from the host computer’s keyboard are parsed and a series of low level

command packets are sent to the command converter. The command converter translates

these low level command packets into serial sequences that are transferred to the target

DSP via its JTAG/OnCE port. The JTAG/OnCE port provides the necessary control to the

target so programs may be loaded or saved, registers read or modified, and hardware

breakpoints set or cleared.

The host computer interface is designed to communicate with as many as eight command

converter cards. This requires a special software protocol to avoid data collisions between

one target and another. The purpose of this section is to describe the subsystem

components of the ADS to give a better understanding of the communication link between

the user and the target DSP.

3.1 Host Computer Hardware

The host computer’s hardware interface provides the communications link between the

user and the command converter. The ADS user interface program uses a software

handshake when communicating with the command converter. There are signals defined

on the host computer bus interface card which are used for requesting and acknowledging

information transfer. Since the handshake is software driven the transfer rate will be

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Motorola Command One Manuel d'utilisateur Page 33