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Chapter 5 Background Debug Controller (S12ZBDCV2)
MC9S12ZVM Family Reference Manual Rev. 1.3
Freescale Semiconductor
163
5.4.4.8
GO_UNTIL
This command is used to exit active BDM and begin (or resume) execution of application code. The CPU
pipeline is flushed and refilled before normal instruction execution resumes. Prefetching begins at the
current address in the PC. If any register (such as the PC) is altered by a BDC command whilst in BDM,
the updated value is used when prefetching resumes.
After resuming application code execution, if ACK is enabled, the BDC awaits a return to active BDM
before driving an ACK pulse. timeouts do not apply when awaiting a GO_UNTIL command ACK.
If a GO_UNTIL is not acknowledged then a SYNC command must be issued to end the pending
GO_UNTIL.
If a GO_UNTIL command is issued whilst BDM is inactive, an illegal command response is returned and
the ILLCMD bit is set.
If ACK handshaking is disabled, the GO_UNTIL command is identical to the GO command.
5.4.4.9
NOP
NOP performs no operation and may be used as a null command where required.
5.4.4.10
READ_Rn
This command reads the selected CPU registers and returns the 32-bit result. Accesses to CPU registers
are always 32-bits wide, regardless of implemented register width. Bytes that are not implemented return
Go Until
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Read CPU register
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0x60+CRN
Data [31-24] Data [23-16]
Data [15-8]
Data [7-0]
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