I have a number of BLE modules I bought from various distributors (yes, Aliexpress was one...) to test and set up a reasonable development environment for creating fairly basic BLE devices.
One of them is a WT51822-S4AT module with an NRF51822 which, according to OpenOCD, is revision 1 (nRF51822-QFAA(build code: CA/C0). The others are NRF52 based - with one other NRF51822, but that's revision 3. I have this revision 3 device tested with Arduino, but will set up VisualStudio Code for actual development (Arduino environment was just for confirming hardware).
So, I'm stuck with just one module, revision 1 hardware and would like to put it to some use - nothing major, perhaps a small BLE remote for android. However, after googling and coming across this forum it seems, since the revision 1 is so old I would need a softdevice S110 v5.2.1, and nrf51 SDK 4.4.2 according to this post: nRF51822 revision 1 programming
I managed to download the softdevice hex, and the ZIP of the SDK 4.4.2, but am unsure what development environment to use. It seems NRF Connect is too recent to work with the old revision 1, so using Segger (free license for nrf51822), or Visualstudio code (with NRF Connect extension) are out. Would I have to set up eclipse? And if so, are all that is needed is the IDE, the SDK, and softdevice? I can flash using STlinkv2 and OpenOCD so hardware connection won't be a problem. But setting up the toolchain seems like much more work than just what I've mentioned.
Its a pain to do this just for one device, but would be nice to put it to work, even if its just a small BLE test application. Perhaps the trial version of Keil IDE?