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--- dev:nab:v2:jtag [2015/11/12 13:38] – created redox
+++ dev:nab:v2:jtag [2023/11/24 22:18] (current) – redox
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+<!DOCTYPE markdown>
 # JTAG access
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 {{:dev:nab:v2:jtag:bbv3.jpg?200 |}}I think you can use any JTAG probe that's 3.3v compatible, if you have one. If you don't, I recommend the [BusBlaster v3](http://dangerousprototypes.com/docs/Bus_Blaster_v3_design_overview). It's a great board, versatile and cheap; oh ! and it's also open hardware and open source ! :-)
-On of the best features of the BusBlaster is you can reconfigure the CPLD to emulate any FT2232 JTAG probe. I think it comes pre-programmed with a JTAGkey buffer logic, which should work fine for this application.
+One of the best features of the BusBlaster is you can reconfigure the CPLD to emulate any FT2232 JTAG probe. I think it comes pre-programmed with a JTAGkey buffer logic, which should work fine for this application.
 _Note_: My BusBlaster (a v4 !) uses a KT-link buffer logic, because I needed the SWD capabilities for another application. If the following steps don't work, try to reprogram the CPLD with a KT-link buffer and try again !
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     ./openocd -f nabaztagv2.cfg
+## GDB
+I think you can use telnet to interact with OpenOCD, but I use GDB... Here are a few notes:
+### Launch and connect
+    arm-none-eabi-gdb
+or, if you have an .elf file to debug/flash
+    arm-none-eabi-gdb ./path/to/file.elf
+Once in GDB
+    tar ext :3333
+The Nabaztag should have "frozen". you can (always) restart it with
+    mon reset run
+### Dump the flash
+    mon reset init
+    dump ihex memory dump.hex 0x08000000 0x08020000 # Get an hex file, useful for analyzing it
+    dump binary memory dump.bin 0x08000000 0x08020000 # Get a bin file, useful for backup and restore
+_Note_: The files end up in the same folder as the openocd binary (or the folder from where you run it)
+### Write an image
+    mon reset init
+    mon flash write_image erase ./dump.bin 0x08000000
+_Note_: The files should be in the same folder as the openocd binary (or the folder from where you run it)
 ## Pictures
 {{.:jtag:nabjtag.jpg?250| BusBlaster connected to the Nabaztag, side view}} {{.:jtag:nabjtag_bottom.jpg?250| BusBlaster connected to the Nabaztag, bottom view}}
+### Flash an elf file
+If you started GDB with an elf file (or if you loaded one), you can flash it on the Nabaztag by simply running:
+    load
 ## Links
+* [BusBlaster wiki](http://dangerousprototypes.com/docs/Bus_Blaster)
+* [OpenOCD user guide](http://openocd.org/doc/html/)