Freescale Semiconductor MC9S12G128 Evaluation Board TWR-S12G128-KIT TWR-S12G128-KIT Ficha De Dados
Códigos do produto
TWR-S12G128-KIT
Background Debug Module (S12SBDMV1)
MC9S12G Family Reference Manual,
Rev.1.23
298
Freescale Semiconductor
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.
locations unobtrusively, even if the addresses conflict with the application memory map.
7.4.4
Standard BDM Firmware Commands
BDM firmware commands are used to access and manipulate CPU resources. The system must be in active
BDM to execute standard BDM firmware commands, see
BDM to execute standard BDM firmware commands, see
.
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.
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 0x3_FF00–0x3_FFFF, and the CPU begins executing the standard
BDM firmware. The standard BDM firmware watches for serial commands and executes them as they are
received.
visible in the on-chip memory map at 0x3_FF00–0x3_FFFF, 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 7-5. Hardware Commands
Command
Opcode
(hex)
Data
Description
BACKGROUND
90
None
Enter background mode if BDM is enabled. If enabled, an ACK will be issued
when the part enters active background mode.
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
16-bit data out
Read from memory with standard BDM firmware lookup table in map.
Odd address data on low byte; even address data on high byte.
Odd address data on low byte; even address data on high byte.
READ_BD_WORD
EC
16-bit address
16-bit data out
Read from memory with standard BDM firmware lookup table in map.
Must be aligned access.
Must be aligned access.
READ_BYTE
E0
16-bit address
16-bit data out
Read from memory with standard BDM firmware lookup table out of map.
Odd address data on low byte; even address data on high byte.
Odd address data on low byte; even address data on high byte.
READ_WORD
E8
16-bit address
16-bit data out
Read from memory with standard BDM firmware lookup table out of map.
Must be aligned access.
Must be aligned access.
WRITE_BD_BYTE
C4
16-bit address
16-bit data in
Write to memory with standard BDM firmware lookup table in map.
Odd address data on low byte; even address data on high byte.
Odd address data on low byte; even address data on high byte.
WRITE_BD_WORD
CC
16-bit address
16-bit data in
Write to memory with standard BDM firmware lookup table in map.
Must be aligned access.
Must be aligned access.
WRITE_BYTE
C0
16-bit address
16-bit data in
Write to memory with standard BDM firmware lookup table out of map.
Odd address data on low byte; even address data on high byte.
Odd address data on low byte; even address data on high byte.
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.
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.
complete for all BDM WRITE commands.