You can get started with esp32 for $5. Nordic devkits are more expensive, and going past that requires a JTAG programmer, which is an expensive option for hobbyists and students.
It's not surprising that they have taken off like they have. Initially it was because it was inexpensive, but now the community is huge and that is a very attractive selling point.
You can get a BBC micro:bit with Nordic SoC for $15
Not exactly $5, but not very expensive either
There's also a decent growing community around them
You've also got the nRF52 USB dongle which seems similar to those cheaper ESP32 kits, for around $10.
> and going past that requires a JTAG programmer
No, the official Nordic devkits comes with a built-in debugger. Same for micro:bit. It's just plain USB.
That said, I do think Nordic could be better at penetrating the hobbyist/student market. I think one problem is the lack of a combined BT/WiFi chip.
I think once Zephyr becomes more mature and there's more tutorials/guides around it, a good BT+Thread+WiFi solution from Nordic could become very popular. Zephyr is a bit hard to get into, but incredibly powerful once you get used to it.
> No, the official Nordic devkits comes with a built-in debugger. Same for micro:bit. It's just plain USB.
Right, the devkits can do this. If you want to go past that, like making your own PCB with a NRF52 on it you need JTAG, which is not a requirement for esp32.
Maybe the NRF52 has some sort of ROM serial loader that I've missed though.
It’s actually possible to use the debugger on the NRF dev kits to flash/debug custom PCBs with NRF chips. So a separate (more expensive) JTAG debugger is in fact not required.
Yes nrf dev boards have an on board j-link, and Nordic provides instructions on how to turn the board into a programmer. Their licensing with segger explicitly allows this as long as you use it for other Nordic devices. Much cheaper than a standalone j-link.
You can load Black Magic Probe firmware on a bluepill and have JTAG for about $2. I also ported it to nRF52840 if you have an extra dongle laying around. Or esp8266 for debugging over wifi (wireless JTAG is super useful sometimes.)
Segger has been really successful at marketing "JTAG == JLink" but it is just not true.
GDB options for debugging/flashing can be had for sub 10eur, Segger is not mandatory. Moreover, the onboard Segger of the devkit can be used externally on Nordic MCUs in custom products and is covered by the licensing agreement between Nordic and Segger for this usecase.
For $9.90 you get a Seeed Xiao NRF52840[1] board with Arduino support. In sleep mode it consumes just 1µA. In my spare time I'm building smart locks with these that last for up to 2 years with a CR123 battery. Recently I switched from Arduino to the nrf Connect SDK and a tiny nrf52832 board that cost just 4$ on AliExpress. Works like a charm.
With SWD and a Tag-Connect connector[1]. I watched someone on youtube recommend it due to the small space and low profile. You can use the VSCode NRF Connect SDK plugin (coupled with Jlink or NRF52 dev kit) to flash the device. But of course you can just use USB und copy a generated .hex file directly on the device. I use SWD because its faster to flash many boards by just pressing the pogo pins on the connector pad. Boom done. :)
It's not surprising that they have taken off like they have. Initially it was because it was inexpensive, but now the community is huge and that is a very attractive selling point.