Chapter 5 Background Debug Controller (S12ZBDCV2)
S12ZVHY/S12ZVHL Family Reference Manual Rev. 1.05
Freescale Semiconductor
157
with the CPU. An ACK pulse is issued by the target device after this command is executed. This command
can be used by the host to evaluate if the target supports the hardware handshake protocol. If the target
supports the hardware handshake protocol, subsequent commands are enabled to execute the hardware
handshake protocol, otherwise this command is ignored by the target.
indicates which
commands support the ACK hardware handshake protocol.
For additional information about the hardware handshake protocol, refer to
and
5.4.4.4
BACKGROUND
Provided ENBDC is set, the BACKGROUND command causes the target MCU to enter active BDM as
soon as the current CPU instruction finishes. If ENBDC is cleared, the BACKGROUND command is
ignored.
A delay of 16 BDCSI clock cycles is required after the BACKGROUND command to allow the target
MCU to finish its current CPU instruction and enter active background mode before a new BDC command
can be accepted.
The host debugger must set ENBDC before attempting to send the BACKGROUND command the first
time. Normally the host sets ENBDC once at the beginning of a debug session or after a target system reset.
During debugging, the host uses GO commands to move from active BDM to application program
execution and uses the BACKGROUND command or DBG breakpoints to return to active BDM.
A BACKGROUND command issued during stop or wait modes cannot immediately force active BDM
because the WAI instruction does not end until an interrupt occurs. For the detailed mode dependency
description refer to
.
The host can recognize this pending BDM request condition because both NORESP and WAIT are set, but
BDMACT is clear. Whilst in wait mode, with the pending BDM request, non-intrusive BDC commands
are allowed.
5.4.4.5
DUMP_MEM.sz, DUMP_MEM.sz_WS
Enter active background mode (if enabled)
Non-intrusive
0x04
host
target
D
A
C
K
DUMP_MEM.sz
Read memory specified by debug address register, then
increment address
Non-intrusive
0x32
Data[7-0]
