Application Note

AN2104

2

When the BDM is active, it takes over control of the microprocessor,

which allows for debugging, etc.

Other examples of what the BDM can be used for, besides debugging,

vary from programming EPROM, EEPROM, and FLASH (internal and

external) to performing calibration on a target application (in

manufacturing and in the field) to transferring collected and stored

information to another system.

Theory of Operation

Because software packages, such as P&E Microcomputer Systems’

Windows Development Package (PKG12), take care of the operation of

the BDM, this discussion does not go into great detail. For more in-depth

information on this subject, refer to the documents referenced in

Technical Resources at the end of this document.

The operation of the BDM system requires a host PC with software, a

BDM interface POD or BDM interface, and the user’s target application.

See Figure 1. The host PC is connected to the POD with a DB-25

parallel cable from the PC’s parallel port. The POD is then connected to

the target application via a custom 6-pin BDM connector and cable. See

Figure 2.

Figure 1. BDM System

HOST PC

INTERFACE POD

BDM INTERFACE

TARGET BOARD

PARALLEL

CABLE

CABLE12 FROM P&E

MICROCOMPUTER SYSTEMS

BDM

CABLE

6-PIN BDM CONNECTOR

SEE FIGURE 2

Freescale Semiconductor, Inc.

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