HCS12 datasheet(12/34 Pages) MOTOROLA

12 / 34 page

Block Guide — S12BDM V4

3.1 BDM Status Register

Figure 3-1 BDM Status Register (BDMSTS)

Read: All modes through BDM operation

Write: All modes but subject to the following:

–

BDMACT can only be set by BDM hardware upon entry into BDM. It can only be cleared by

the standard BDM firmware lookup table upon exit from BDM active mode.

–

CLKSW can only be written via BDM hardware or standard BDM firmware write commands.

–

All other bits, while writable via BDM hardware or standard BDM firmware write commands,

should only be altered by the BDM hardware or standard firmware lookup table as part of BDM

command execution.

–

ENBDM should only be set via a BDM hardware command if the BDM firmware commands

are needed. (This does not apply in Special Single-Chip Mode).

ENBDM — Enable BDM

This bit controls whether the BDM is enabled or disabled. When enabled, BDM can be made active to

allow firmware commands to be executed. When disabled, BDM cannot be made active but BDM

hardware commands are still allowed.

1 = BDM enabled

0 = BDM disabled

NOTE:

ENBDM is set by the firmware immediately out of reset in special single-chip mode.

In secure mode, this bit will not be set by the firmware until after the EEPROM and

FLASH erase verify tests are complete.

ENBDM

BDMACT

ENTAG

SDV

TRACE

CLKSW

UNSEC

Reset:

Special single-chip mode:

Special peripheral mode:

All other modes:

= Unimplemented or Reserved

HCS12 Datasheet(PDF) 12 Page - Motorola, Inc