hic_docs: add section about J-Link OB for sam3u2c HIC

Author: mbrossard

docs/hic/sam3u2c.md

@@ -33,3 +33,36 @@ Bootloader size is 32 KB
 | HID LED     |  O  | PA29    |  85 |
 | MSD LED     |  O  | PA28    |  84 |
 | CDC LED     |  O  | PA31    |  86 |
+
+# J-Link OB SAM3U128
+
+## Warning
+
+The SEGGER design suggests a change to the pin assignment of the TC2050-IDC
+used to debug the HIC MCU. They suggest replacing GNDDetect by power-supply
+(VBus, V5), which could create a short with standard Tag-Connect cables and
+SWD probes.
+
+## J-Link OB SAM3U128 pin assignment
+
+| Signal      | I/O | Symbol  | Pin |
+|-------------|:---:|---------|:---:|
+| SWD / JTAG  |
+| SWCLK / TCK |  O  | PA17    |  14 |
+| SWCLK / TCK |  I  | PA22    |   5 |
+| SWDIO / TMS |  O  | PA18    |  17 |
+| SWDIO / TMS |  I  | PA15    |  12 |
+| TDI         |  O  | PA20    |  19 |
+| TDI         |  I  | PA13    |  10 |
+| SWO / TDO   |  I  | PA21    |  20 |
+| nRESET      |  O  | PA4     |  30 |
+| nRESET      |  I  | PA3     |  29 |
+| UART        |
+| UART TX     |  O  | PA12    |  41 |
+| UART RX     |  I  | PA11    |  40 |
+| Button      |
+| NF-RST But. |  O  | PA1     |  27 |
+| NF-RST But. |  I  | PA0     |  26 |
+| LEDs        |
+| LED1        |  O  | PA29    |  85 |
+| LED2        |  O  | PA28    |  84 |