MC9S12NE64_06 Datasheet, PDF (454/554 Pages) Freescale Semiconductor, Inc – Microcontrollers

Chapter 17 Background Debug Module (BDMV4)
The BDM hardware commands are listed in Table 17-5.
Table 17-5. Hardware Commands
Command
Opcode
(hex)
Data
Description
BACKGROUND
90
None
Enter background mode if firmware is enabled. If enabled, an ACK will
be issued when the part enters active background mode.
ACK_ENABLE
D5
None
Enable handshake. Issues an ACK pulse after the command is
executed.
ACK_DISABLE
D6
None
Disable handshake. This command does not issue an ACK pulse.
READ_BD_BYTE
E4
16-bit address Read from memory with standard BDM firmware lookup table in map.
16-bit data out Odd address data on low byte; even address data on high byte.
READ_BD_WORD
EC
16-bit address Read from memory with standard BDM firmware lookup table in map.
16-bit data out Must be aligned access.
READ_BYTE
E0
16-bit address Read from memory with standard BDM firmware lookup table out of
16-bit data out map. Odd address data on low byte; even address data on high byte.
READ_WORD
E8
16-bit address Read from memory with standard BDM firmware lookup table out of
16-bit data out map. Must be aligned access.
WRITE_BD_BYTE
C4
16-bit address Write to memory with standard BDM firmware lookup table in map. Odd
16-bit data in address data on low byte; even address data on high byte.
WRITE_BD_WORD
CC
16-bit address Write to memory with standard BDM firmware lookup table in map. Must
16-bit data in be aligned access.
WRITE_BYTE
C0
16-bit address Write to memory with standard BDM firmware lookup table out of map.
16-bit data in Odd address data on low byte; even address data on high byte.
WRITE_WORD
C8
16-bit address Write to memory with standard BDM firmware lookup table out of map.
16-bit data in Must be aligned access.
NOTE:
If enabled, ACK will occur when data is ready for transmission for all BDM READ commands and will occur after the write is
complete for all BDM WRITE commands.
The READ_BD and WRITE_BD commands allow access to the BDM register locations. These locations
are not normally in the system memory map but share addresses with the application in memory. To
distinguish between physical memory locations that share the same address, BDM memory resources are
enabled just for the READ_BD and WRITE_BD access cycle. This allows the BDM to access BDM
locations unobtrusively, even if the addresses conflict with the application memory map.
17.4.4 Standard BDM Firmware Commands
Firmware commands are used to access and manipulate CPU resources. The system must be in active
BDM to execute standard BDM firmware commands, see Section 17.4.2, “Enabling and Activating
BDM.” Normal instruction execution is suspended while the CPU executes the firmware located in the
standard BDM firmware lookup table. The hardware command BACKGROUND is the usual way to
activate BDM.
As the system enters active BDM, the standard BDM firmware lookup table and BDM registers become
visible in the on-chip memory map at 0xFF00–0xFFFF, and the CPU begins executing the standard BDM
MC9S12NE64 Data Sheet, Rev. 1.1
454
Freescale Semiconductor