M68HC128 Datasheet, PDF (324/362 Pages) Motorola, Inc – Microcontrollers

Freescale Semiconductor, Inc.
Development Support
18.3.5.2 Firmware Command
Address: $FF00
Bit 7
6
5
Read:
H/F
DATA
R/W
Write:
Reset: 0
0
0
4
3
TTAGO
0
0
2
1
Bit 0
REGN
0
0
0
Figure 18-5. BDM Instruction Register (INSTRUCTION)
The bits in the BDM instruction register have these meanings when a firmware
command is executed.
H/F — Hardware/Firmware Flag
0 = Firmware control logic
1 = Hardware control logic
DATA — Data Flag
0 = No data
1 = Data included in command
R/W — Read/Write Flag
0 = Write
1 = Read
TTAGO — Trace, Tag, Go Field
Table 18-5. TTAGO Decoding
TTAGO Value
00
01
10
11
Instruction
—
GO
TRACE1
TAGGO
REGN — Register/Next Field
Indicates which register is being affected by a command. In the case of a
READ_NEXT or WRITE_NEXT command, index register X is pre-incremented
by two and the word pointed to by X is then read or written.
Table 18-6. REGN Decoding
TTAGO Value
000
001
010
011
Instruction
—
—
READ/WRITE NEXT
PC
Data Sheet
324
Development Support
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M68HC12B Family — Rev. 9.0
MOTOROLA