Pod Mode - Motorola M68EVB912B32 User Manual

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3.1.2 JUMP-EEPROM Mode. Control can be returned to the D-Bug12 terminal prompt by

doing one of the following:

1. terminating the user code with appropriate instructions — see section 3.1.2

2. pressing the reset button (S1)

3.2.2.3 POD Mode

In POD mode, the host EVB serves as a non-intrusive controller for the target system via the

BDM interface. The host EVB begins executing code at the address contained in the alternate

reset vector at $F7FE (for information on the alternate reset and interrupt vector table, see Vector

Jump Table: Interrupt and Reset Addresses on page E-4). The code pointed to by the

alternate reset vector may either be D-Bug12 (factory default) or a user's program that has

replaced D-Bug12 in Flash EEPROM.

D-Bug12  upon power-up or reset, D-Bug12 attempts to establish communications with a

target system connected to BDM OUT (W11). Communications are first attempted

without resetting the target system.

following message is displayed:

Can't Communicate With The Target Processor

To reset target, hit any key...

Pressing any key on the terminal's keyboard causes D-Bug12 to assert the target's reset

pin for approximately 2 mS and try again to establish communications.

communications fail, the above error message is redisplayed. Once communications have

been established with the target system, the D-Bug12 sign-on banner and prompt should

appear on the terminal's display as follows:

D-Bug12 v 2.0.0

For Commands type "Help"

If communications cannot be established with the target system after repeated attempts,

check for the following possible problems:

• The host EVB's BDM OUT (W11) must be properly connected to the target system's

BDM connector. If the target system is another EVB, make sure that the host EVB's

BDM OUT is connected to target EVB's BDM IN (W9).

• If the target system is not another EVB, verify that its BDM connector is wired to the

proper MCU signals on each pin.

• If the target MCU does not have any firmware to execute, it could "run away,"

possibly executing a STOP opcode and preventing BDM communications with the

host EVB.

Thus, it is strongly recommended that, if the target system does not have firmware to

execute at reset, the target MCU be initially configured to begin operation in Special

68EVB912B32UM/D

If communications cannot be established, the

OPERATION

3-5

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