In the image below you can see the debug test points along with the with wires soldered to them to connect to my debugger. This enables the debugger to become another AMBA bus master for access to system memory and peripheral or debug registers. SWD uses an ARM CPU standard bi-directional wire protocol, defined in the ARM Debug Interface v5. Serial Wire Debug (SWD) is a 2-pin (SWDIO/SWCLK) electrical alternative JTAG interface that has the same JTAG protocol on top. This is the same interface that STM32 chips utilize and it provides similar functionality as a “standard” JTAG interface. I was able to find the SWDIO, SWCLK, +3.3 and GND connections for the Serial Wire Debug (SWD) debug interface. Since the board was well labeled I didn’t need to use any tools like a JTAGulator or an Arduino board with the JTAGenum firmware to identify which test points are the debug interface. This processor looks to be the primary processor for the device and has the most valuable firmware. Now that I have the lay of the land for the device (which that I outlined in my previous part of the series) the first thing I looked for is the debugging connections for the main GigaDevices processor. This is a continuation from a previous post: Finding the connections

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