added comments for JLink connection work.
* This file is part of the TinyUSB stack.
*/
+/* How to connect JLink and GR-CITRUS
+ *
+ * GR-CITRUS needs to solder some pads to enable JTAG interface.
+ * - Short the following pads individually with solder.
+ * - J4
+ * - J5
+ * - Short EMLE pad and 3.3V(GR-CITRUS pin name) with a wire.
+ *
+ * The pads are [the back side of GR-CITRUS](https://www.slideshare.net/MinaoYamamoto/grcitrusrx631/2).
+ *
+ * Connet the pins between GR-CITRUS and JLink as follows.
+ *
+ * | JTAG Function | GR-CITRUS pin name| JLink pin No.| note |
+ * |:-------------:|:-----------------:|:------------:|:--------:|
+ * | VTref | 3.3V | 1 | |
+ * | TRST | 5 | 3 | |
+ * | GND | GND | 4 | |
+ * | TDI | 3 | 5 | |
+ * | TMS | 2 | 7 | |
+ * | TCK | 14 | 9 | short J4 |
+ * | TDO | 9 | 13 | short J5 |
+ * | nRES | RST | 15 | |
+ *
+ * JLink firmware needs to update to V6.96 or newer version to avoid
+ * [a bug](https://forum.segger.com/index.php/Thread/7758-SOLVED-Bug-in-JLink-from-V6-88b-regarding-RX65N)
+ * regarding downloading.
+ *
+ * When using SEGGER RTT, `RX_NEWLIB=0` should be added to make command arguments.
+ * The option is used to change the C runtime library to `optlib` from `newlib`.
+ * RTT may not work with `newlib`.
+ */
+
#include "../board.h"
#include "iodefine.h"
#include "interrupt_handlers.h"
