MC68HC912B32 Datasheet, PDF (122/128 Pages) Motorola, Inc – 16-Bit Microcontroller

STATUS — BDM Status Register
Bit 7
6
5
4
3
2
ENBDM BDMACT ENTAG SDV TRACE
0
RESET:
0
0
0
1
0
0
(BDM) $FF01
1
Bit 0
0
0
0
0
This register can be read or written by BDM commands or firmware.
ENBDM — Enable BDM (permit active background debug mode)
0 = BDM cannot be made active (hardware commands still allowed)
1 = BDM can be made active to allow firmware commands
BDMACT — Background Mode Active Status
0 = BDM not active
1 = BDM active and waiting for serial commands
ENTAG — Instruction Tagging Enable
Set by the TAGGO instruction and cleared when BDM is entered.
0 = Tagging not enabled, or BDM active
1 = Tagging active (BDM cannot process serial commands while tagging is active.)
SDV — Shifter Data Valid
Shows that valid data is in the serial interface shift register. Used by firmware-based instructions.
0 = No valid data
1 = Valid Data
TRACE — Asserted by the TRACE1 instruction
SHIFTER — BDM Shift Register
Bit 15
14
13
12
11
10
S15
S14
S13
S12
S11
S10
(BDM) $FF02, $FF03
9
Bit 8
S9
S8
Bit 7
6
5
4
3
2
1
Bit 0
S7
S6
S5
S4
S3
S2
S1
S0
This 16-bit register contains data being received or transmitted via the serial interface.
ADDRESS — BDM Address Register
(BDM) $FF04, $FF05
Bit 15
14
13
12
11
10
9
Bit 8
A15
A14
A13
A12
A11
A10
A9
A8
Bit 7
6
5
4
3
2
1
Bit 0
A7
A6
A5
A4
A3
A2
A1
A0
This 16-bit register is temporary storage for BDM hardware and firmware commands.
CCRSAV — BDM CCR Holding Register
(BDM) $FF06
Bit 7
6
5
4
3
2
1
Bit 0
CCR7 CCR6 CCR5 CCR4 CCR3 CCR2 CCR1 CCR0
This register preserves the content of the CPU12 CCR while BDM is active.
MOTOROLA
122
MC68HC912B32
MC68HC912B32TS/D