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