Specifications
Table Of Contents
- ARM Debugger
- Brief Overview of Documents for New Users
- Warning
- Quick Start of the JTAG Debugger
- Troubleshooting
- FAQ
- Trace Extensions
- Symmetric Multiprocessing
- ARM Specific Implementations
- ARM specific SYStem Commands
- SYStem.BdmClock Define JTAG frequency
- SYStem.CLOCK Inform debugger about core clock
- SYStem.CONFIG Configure debugger according to target topology
- SYStem.CPU Select the used CPU
- SYStem.CpuAccess Run-time memory access (intrusive)
- SYStem.JtagClock Define JTAG frequency
- SYStem.LOCK Tristate the JTAG port
- SYStem.MemAccess Run-time memory access
- SYStem.Mode Establish the communication with the target
- SYStem.Option ABORTFIX Do not access 0x0-0x1f
- SYStem.Option AHBHPROT Select AHB-AP HPROT bits
- SYStem.Option AMBA Select AMBA bus mode
- SYStem.Option ASYNCBREAKFIX Asynchronous break bugfix
- SYStem.Option AXIACEEnable ACE enable flag of the AXI-AP
- SYStem.Option AXICACHEFLAGS Select AXI-AP CACHE bits
- SYStem.Option AXIHPROT Select AXI-AP HPROT bits
- SYStem.Option BUGFIX Breakpoint bug fix
- SYStem.Option BUGFIXV4 Asynch. break bug fix for ARM7TDMI-S REV4
- SYStem.Option BigEndian Define byte order (endianess)
- SYStem.Option BOOTMODE Define boot mode
- SYStem.Option CINV Invalidate the cache after memory modification
- SYStem.Option CFLUSH FLUSH the cache before step/go
- SYStem.Option CacheParam Define external cache
- SYStem.Option DACR Debugger ignores DACR access permission settings
- SYStem.Option DAPNOIRCHECK No DAP instruction register check
- SYStem.Option DAPREMAP Rearrange DAP memory map
- SYStem.Option DBGACK DBGACK active on debugger memory accesses
- SYStem.Option DBGNOPWRDWN DSCR bit 9 will be set when in debug mode
- SYStem.Option DBGUNLOCK Unlock debug register via OSLAR
- SYStem.Option DCDIRTY Bugfix for erroneously cleared dirty bits
- SYStem.Option DCFREEZE Disable data cache linefill in debug mode
- SYStem.Option DIAG Activate more data.log messages
- SYStem.Option DisMode Define disassembler mode
- SYStem.Option DynVector Dynamic trap vector interpretation
- SYStem.Option EnReset Allow the debugger to drive nRESET/nSRST
- SYStem.Option ETBFIXMarvell Read out on-chip trace data
- SYStem.Option ETMFIX Shift data of ETM scan chain by one
- SYStem.Option ETMFIXWO Bugfix for write-only ETM register
- SYStem.Option ETMFIX4 Use only every fourth ETM data package
- SYStem.Option EXEC EXEC signal can be used by bustrace
- SYStem.Option EXTBYPASS Switch off the fake TAP mechanism
- SYStem.Option FASTBREAKDETECTION Faster detection if core has halted
- SYStem.Option ICEBreakerETMFIXMarvell Lock on-chip breakpoints
- SYStem.Option ICEPICKONLY Only ICEPick registers accessible
- SYStem.Option IMASKASM Disable interrupts while single stepping
- SYStem.Option IMASKHLL Disable interrupts while HLL single stepping
- SYStem.Option INTDIS Disable all interrupts
- SYStem.Option IRQBREAKFIX Break bugfix by using IRQ
- SYStem.Option IntelSOC Debugging of an Intel SOC
- SYStem.Option KEYCODE Define key code to unsecure processor
- SYStem.Option L2Cache L2 cache used
- SYStem.Option L2CacheBase Define base address of L2 cache register
- SYStem.Option LOCKRES Go to "Test-Logic Reset" when locked
- SYStem.Option MEMORYHPROT Select memory-AP HPROT bits
- SYStem.Option MMUSPACES Enable multiple address spaces support
- SYStem.Option MonitorHoldoffTime Delay between monitor accesses
- SYStem.Option MPU Debugger ignores MPU access permission settings
- SYStem.Option MultiplesFIX No multiple loads/stores
- SYStem.Option NODATA No data connected to the trace
- SYStem.Option NOIRCHECK No JTAG instruction register check
- SYStem.Option NoPRCRReset Do not cause reset by PRCR
- SYStem.Option NoRunCheck No check of the running state
- SYStem.Option NoSecureFix Do not switch to secure mode
- SYStem.Option OVERLAY Enable overlay support
- SYStem.Option PALLADIUM Extend debugger timeout
- SYStem.Option PC Define address for dummy fetches
- SYStem.Option PROTECTION Sends an unsecure sequence to the core
- SYStem.Option PWRCHECK Check power and clock
- SYStem.Option PWRCHECKFIX Check power and clock
- SYStem.Option PWRDWN Allow power-down mode
- SYStem.Option PWRDWNRecover Mode to handle special power recovery
- SYStem.Option PWRDWNRecoverTimeOut Timeout for power recovery
- SYStem.Option PWROVR Specifies power override bit
- SYStem.Option ResBreak Halt the core after reset
- SYStem.Option ResetDetection Choose method to detect a target reset
- SYStem.Option RESTARTFIX Wait after core restart
- SYStem.Option RisingTDO Target outputs TDO on rising edge
- SYStem.Option ShowError Show data abort errors
- SYStem.Option SOFTLONG Use 32-bit access to set breakpoint
- SYStem.Option SOFTQUAD Use 64-bit access to set breakpoint
- SYStem.Option SOFTWORD Use 16-bit access to set breakpoint
- SYStem.Option SPLIT Access memory depending on CPSR
- SYStem.Option StandByTraceDelaytime Delay for activating trace after reset
- SYStem.Option STEPSOFT Use software breakpoints for ASM stepping
- SYStem.Option SYSPWRUPREQ Force system power
- SYStem.Option TIDBGEN Activate initialization for TI derivatives
- SYStem.Option TIETMFIX Bug fix for customer specific ASIC
- SYStem.Option TIDEMUXFIX Bug fix for customer specific ASIC
- SYStem.Option TraceStrobe Obsolete command
- SYStem.Option TRST Allow debugger to drive TRST
- SYStem.Option TURBO Speed up memory access
- SYStem.Option WaitReset Wait with JTAG activities after deasserting reset
- SYStem.Option ZoneSPACES Enable symbol management for ARM zones
- SYStem.RESetOut Assert nRESET/nSRST on JTAG connector
- SYStem.view Display SYStem window
- ARM Specific Benchmarking Commands
- ARM Specific TrOnchip Commands
- TrOnchip.A Programming the ICE breaker module
- TrOnchip.A.Value Define data selector
- TrOnchip.A.Size Define access size for data selector
- TrOnchip.A.CYcle Define access type
- TrOnchip.A.Address Define address selector
- TrOnchip.A.Trans Define access mode
- TrOnchip.A.Extern Define the use of EXTERN lines
- TrOnchip.AddressMask Define an address mask
- TrOnchip.ContextID Enable context ID comparison
- TrOnchip.CONVert Extend the breakpoint range
- TrOnchip.Mode Configure unit A and B
- TrOnchip.RESet Reset on-chip trigger settings
- TrOnchip.Set Set bits in the vector catch register
- TrOnchip.TEnable Define address selector for bus trace
- TrOnchip.TCYcle Define cycle type for bus trace
- TtrOnchip.VarCONVert Convert variable breakpoints
- TrOnchip.view Display on-chip trigger window
- CPU specific MMU Commands
- Target Adaption
- Support
- Products
ARM Debugger 2 8 A R M S p e c i f i c I m p l e m e n t a t i o n s
©1989-2014 Lauterbach GmbH
Semihosting
Semihosting is a technique for an application program running on an ARM processor to communicate with
the host computer of the debugger. This way the application can use the I/O facilities of the host computer
like keyboard input, screen output, and file I/O. This is especially useful if the target platform does not yet
provide these I/O facilities or in order to output additional debug information in printf() style.
A semihosting call from the application causes an exception by a SVC (SWI) instruction together with a
certain SVC number to indicate a semihosting request. The type of operation is passed in R0. R1 points to
the other parameters. On Cortex-M semihosting is implemented using the BKPT instead of SVC instruction.
Normally semihosting is invoked by code within the C library functions of the ARM RealView compiler like
printf() and scanf(). The application can also invoke the operations used for keyboard input, screen output,
and file I/O directly. The operations are described in the RealView Compilation Tools Developer Guide from
ARM in the chapter ‚Semihosting Operations'.
The debugger which needs to interface to the I/O facilities on the host provides two ways to handle a
semihosting request which results in a SVC (SWI) or BKPT exception:
SVC (SWI) Emulation Mode
A breakpoint placed on the SVC exception entry stops the application. The debugger handles the request
while the application is stopped, provides the required communication with the host, and restarts the
application at the address which was stored in the link register R14 on the SVC exception call. Other as for
the DCC mode the SVC parameter has to be 0x123456 to indicate a semihosting request.
This mode is enabled by TERM.METHOD ARMSWI [<address>] and by opening a TERM.GATE window
for the semihosting screen output. The handling of the semihosting requests is only active when the
TERM.GATE window is existing.
On ARM7 an on-chip or software breakpoint needs to be set at address 8 (SWI exception entry). On other
ARM cores also the vector catch register can be used: TrOnchip.Set SWI ON. The Cortex-M does not need
a breakpoint because it already uses the breakpoint instruction BKPT for the semihosting request.
When using the <address> option of the TERM.METHOD ARMSWI [<address>] any memory location with
a breakpoint on it can be used as a semihosting service entry instead of the SVC call at address 8. The
application just needs to jump to that location. After servicing the request the program execution continues at
that address (not at the address in the link register R14). You could for example place a ’BX R14’ command
at that address and hand the return address in R14. Since this method does not use the SVC command no
parameter (0x123456) will be checked to identify a semihosting call.