I'am realy new to nRF52 development. I want to start with a simple demo as shown on www.nordicsemi.com/.../Getting-started-with-the-nRF52-Development-Kit.
What HW do I exactly need to buy to start playing? I have no experience with JLINK at all. Maybe if someone could explain me a little what is JLINK good for?
Thank you in advance.
There is no "exact" HW you would need. If you want to play with nRF52 DK you just need any PC (preferably Windows but it works with MAC and Linux as well) to be able to program ("flash") the board with some FW (which you may use pre-compiled by Nordic or develop/compile yourself). Finally Bleutooth always work as peer to peer so you need to decide what will be the counterpart;) Many examples work with two nRF5x DK boards but in principle you can use any Android/iOS phone or other BLE embedded system (like dev kits from other brands then Nordic) or even Win10 PC or complex system if it has BLE support.
To J-Link: it's a brand from company called SEGGER and it's used for both HW and SW packages which together work as JTAG/SWD debuggers and programmers. This is needed for chips like nRF5x (but also thousands others) because they typically have no ROM bootloader or BIOS to load some application/OS into the memory (like you know from PC). Back to J-Link: it's one of the most popular commercial products in this field, has many different HW options and licenses. Luckily for you every nRF51 or 52 or 52840 DK boards comes with SEGGER J-Link on-board (OB) which is free to use with Nordic and SEGGER SW tools to debug and program any Nordic chip.
Great answer, thanks.
So - to recap - I do not need to buy an external JLINK programmer if I will play only with the DK boards. Its enough to have just the DK boards (because they have the JLINK OB). But if I will want to make an own nRF52-based device with own PCB layout, I can use a JLINK programmer to load the FW into the nRF52 chip. Am I correct?
Additional Q: what are the alternatives for the JLINK programmer?
You are correct, Dusan. You won't need an external JLINK if you only use the DK's.
It might be worth mentioning that you can use the nRFgo Studio or nrfjprog provided by Nordic to flash the FW to your DK's.
If you want to make your own nRF52-based device, you can also use the on-board J-LINK on your DK to load your FW to your custom device.
To the additional question: other major chip vendors for embedded systems such as ST Micro or NXP have their own variants of JTAG/SWD flasher and debugger but as the protocol is standard they are interchangeable to certain extend. So you can see ST-Link or LPC-Link and others. In professional production environment you can see some specialized programmers such as these linked in Nordic Infocenter. There are also certain open-source and "small" business programmers such as IDAP Link from Hoan.