NXP Semiconductors MC9S08SU16 Reference Manual page 536

Background debug controller (BDC)
Command mnemonic
TAGGO
READ_A
READ_CCR
READ_PC
READ_HX
READ_SP
READ_NEXT
READ_NEXT_WS
WRITE_A
WRITE_CCR
WRITE_PC
WRITE_HX
WRITE_SP
WRITE_NEXT
WRITE_NEXT_WS
1. The SYNC command is a special operation that does not have a command code.
The SYNC command is unlike other BDC commands because the host does not
necessarily know the correct communications speed to use for BDC communications
until after it has analyzed the response to the SYNC command.
To issue a SYNC command, the host:
• Drives the BKGD pin low for at least 128 cycles of the slowest possible BDC clock
(The slowest clock is normally the reference oscillator/64 or the self-clocked rate/
64.)
• Drives BKGD high for a brief speedup pulse to get a fast rise time (This speedup
pulse is typically one cycle of the fastest clock in the system.)
• Removes all drive to the BKGD pin so it reverts to high impedance
• Monitors the BKGD pin for the sync response pulse
536
Table 27-1. BDC command summary (continued)
Active BDM/ non-intrusive
Active BDM
Active BDM
Active BDM
Active BDM
Active BDM
Active BDM
Active BDM
Active BDM
Active BDM
Active BDM
Active BDM
Active BDM
Active BDM
Active BDM
Active BDM
MC9S08SU16 Reference Manual, Rev. 5, 4/2017
Coding structure
18/d Same as GO but enable
external tagging (HCS08
devices have no external
tagging pin)
68/d/RD Read accumulator (A)
69/d/RD Read condition code register
(CCR)
6B/d/RD16 Read program counter (PC)
6C/d/RD16 Read H and X register pair
(H:X)
6F/d/RD16
70/d/RD Increment H:X by one then
read memory byte located at
71/d/SS/RD Increment H:X by one then
read memory byte located at
H:X. Report status and data.
48/WD/d Write accumulator (A)
49/WD/d Write condition code register
(CCR)
4B/WD16/d Write program counter (PC)
4C/WD16/d Write H and X register pair
(H:X)
4F/WD16/d Write stack pointer (SP)
50/WD/d Increment H:X by one, then
write memory byte located at
H:X
51/WD/d/SS Increment H:X by one, then
write memory byte located at
H:X. Also report status.
Description
Read stack pointer (SP)
H:X
NXP Semiconductors