Background Debug Module (S12XBDMV2)
MC9S12XHY-Family Reference Manual, Rev. 1.01
208
Freescale Semiconductor
5.4.4
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 5.4.2, “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 0x7FFF00–0x7FFFFF, and the CPU begins executing the standard
BDM firmware. The standard BDM firmware watches for serial commands and executes them as they are
received.
The firmware commands are shown in
Table 5-7
.
WRITE_WORD
C8
16-bit address
16-bit data in
Write to memory with standard BDM firmware lookup table out of map.
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.
Table 5-6. Hardware Commands (continued)
Command
Opcode
(hex)
Data
Description
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