MC68HC12 MOTOROLA [Motorola, Inc], MC68HC12 Datasheet - Page 403

• Manufacturer Part Number: MC68HC12
• Description: The MC68HC912DT128A microcontroller unit (MCU) is a 16-bit device composed of standard on-chip peripherals including a 16-bit central processing unit
• Manufacturer: MOTOROLA [Motorola, Inc]

MC68HC912DT128A — Rev 4.0
MOTOROLA
WRITE_NEXT
READ_NEXT
WRITE_PC
WRITE_SP
Command
READ_PC
READ_SP
WRITE_D
WRITE_X
WRITE_Y
READ_D
READ_X
READ_Y
TRACE1
TAGGO
GO
Opcode (Hex)
and executes them as they are received. The firmware commands are
shown in
Each of the hardware and firmware BDM commands start with an 8-bit
command code (opcode). Depending upon the commands, a 16-bit
address and/or a 16-bit data word is required as indicated in the tables
by the command. All the read commands output 16-bits of data despite
the byte/word implication in the command name.
The external host should wait 150 BDMCLK cycles for a non-intrusive
BDM command to execute before another command is sent. This delay
includes 128 BDMCLK cycles for the maximum delay for a free cycle.For
data read commands, the host must insert this delay between sending
the address and attempting to read the data.In the case of a write
command, the host must delay after the data portion, before sending a
new command, to be sure the write has finished.
The external host should delay about 32 target BDMCLK cycles between
a firmware read command and the data portion of these commands. This
allows the BDM firmware to execute the instructions needed to get the
requested data into the BDM SHIFTER register.
The external host should delay about 32 target BDMCLK cycles after the
data portion of firmware write commands to allow BDM firmware to
65
66
42
45
46
08
18
62
63
64
67
43
44
47
10
Table 20-3. BDM Firmware Commands
Table
16-bit data out
16-bit data out
16-bit data out
16-bit data out
16-bit data out
16-bit data out
16-bit data in
16-bit data in
16-bit data in
16-bit data in
16-bit data in
16-bit data in
Development Support
20-3.
None
None
None
Data
X = X + 2; Read next word pointed to by X
Read program counter
Read D accumulator
Read X index register
Read Y index register
Read stack pointer
X = X + 2; Write next word pointed to by X
Write program counter
Write D accumulator
Write X index register
Write Y index register
Write stack pointer
Go to user program
Execute one user instruction then return to BDM
Enable tagging and go to user program
Description
Background Debug Mode
Development Support
Technical Data
403