Segger J-Link - Page 24

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J-Link / J-Trace (UM08001) © 2004-2017 SEGGER Microcontroller GmbH & Co. KG
17.2.2 Code tracing and data tracing ..................................................................439
17.2.3 J-Trace integration example - IAR Embedded Workbench for ARM.................439
17.3 Embedded Trace Buffer (ETB) ..................................................................443
17.4 Flash programming ................................................................................444
17.4.1 How does flash programming via J-Link / J-Trace work? ..............................444
17.4.2 Data download to RAM............................................................................444
17.4.3 Data download via DCC...........................................................................444
17.4.4 Available options for flash programming....................................................444
17.5 J-Link / J-Trace firmware.........................................................................446
17.5.1 Firmware update....................................................................................446
17.5.2 Invalidating the firmware ........................................................................446
18 Designing the target board for trace ..........................................................................449
18.1 Overview of high-speed board design........................................................450
18.1.1 Avoiding stubs .......................................................................................450
18.1.2 Minimizing Signal Skew (Balancing PCB Track Lengths) ...............................450
18.1.3 Minimizing Crosstalk...............................................................................450
18.1.4 Using impedance matching and termination ...............................................450
18.2 Terminating the trace signal ....................................................................451
18.2.1 Rules for series terminators .....................................................................451
18.3 Signal requirements ...............................................................................452
19 Semihosting ...............................................................................................................453
19.1 Introduction ..........................................................................................454
19.1.1 Advantages ...........................................................................................454
19.1.2 Disadvantages .......................................................................................454
19.2 Debugger support ..................................................................................455
19.3 Implementation .....................................................................................456
19.3.1 SVC instruction ......................................................................................456
19.3.2 Breakpoint instruction.............................................................................456
19.3.3 J-Link GDBServer optimized version .........................................................456
19.4 Communication protocol..........................................................................458
19.4.1 Register R0 ...........................................................................................458
19.4.2 Command SYS_OPEN (0x01) ...................................................................458
19.4.3 Command SYS_CLOSE (0x02) .................................................................459
19.4.4 Command SYS_WRITEC (0x03)................................................................459
19.4.5 Command SYS_WRITE0 (0x04)................................................................459
19.4.6 Command SYS_WRITE (0x05) .................................................................459
19.4.7 Command SYS_READ (0x06) ...................................................................460
19.4.8 Command SYS_READC (0x07) .................................................................460
19.4.9 Command SYS_ISTTY (0x09)...................................................................460
19.4.10 Command SYS_SEEK (0x0A) ...................................................................461
19.4.11 Command SYS_FLEN (0x0C)....................................................................461
19.4.12 Command SYS_REMOVE (0x0E) ...............................................................461
19.4.13 Command SYS_RENAME (0x0F) ...............................................................461
19.4.14 Command SYS_GET_CMDLINE (0x15).......................................................462
19.4.15 Command SYS_EXIT (0x18) ....................................................................462
19.5 Enabling semihosting in J-Link GDBServer .................................................463
19.5.1 SVC variant ...........................................................................................463
19.5.2 Breakpoint variant..................................................................................463
19.5.3 J-Link GDBServer optimized variant..........................................................463
19.6 Enabling Semihosting in J-Link RDI + AXD.................................................464
20 Support and FAQs .....................................................................................................465
20.1 Measuring download speed ......................................................................466
20.1.1 Test environment ...................................................................................466
20.2 Troubleshooting .....................................................................................467
20.2.1 General procedure..................................................................................467
20.2.2 Typical problem scenarios .......................................................................467
20.3 Contacting support .................................................................................469