Datasheet

Chapter 6 Background Debug Module (BDMV4) Block Description
170 MC9S12C-Family / MC9S12GC-Family Freescale Semiconductor
Rev 01.24
6.3.2.1 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).
0xFF01
76543210
R
ENBDM
BDMACT
ENTAG
SDV TRACE
CLKSW
UNSEC 0
W
Reset:
Special single-chip mode:
Special peripheral mode:
All other modes:
1
(1)
0
0
0
1. ENBDM is read as "1" by a debugging environment in Special single-chip mode when the device is not secured or secured
but fully erased (Flash and EEPROM).This is because the ENBDM bit is set by the standard firmware before a BDM command
can be fully transmitted and executed.
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
(2)
0
0
0
2. UNSEC is read as "1" by a debugging environment in Special single-chip mode when the device is secured and fully erased,
else it is "0" and can only be read if not secure (see also bit description).
0
0
0
0
= Unimplemented or Reserved = Implemented (do not alter)
Figure 6-3. BDM Status Register (BDMSTS)
Note: