hr example wont work on top of soft device, s110-s120?,soft device?

Question

Hi, 
 I am knew to BLE and I was able to ran succesfully the blinky project. Now when I load the soft device on and then try to download the hr example if says "Flash download failed Cortex M0". 
 But if I go to nrfGO studio and erase it, I can upload it. Although in the guide says you have to load the soft device first. Any ideas?? 
 Also since I am a newbie I am having issues with understanding what s110-s120 are, what are the differences? what are they? It might seem stupid but I dont know why there are those 4 options (128k-256k). 
 Finally what is a soft device? 
 Thank you in advance!!

Anders Strand · Accepted Answer

A Softdevice: A bluetooth library pre-programmed to a certain memory space on the chip. This is a more fail-safe alternative to including .h and .c files like you normally would. 
 Softdevice 110: Can only be a "slave" or "peripheral" device, which can be connected to from "centrals" or "masters" like a smartphone. 
 Softdevice 120: Can only be the "central" or "master", and can therefore connect to another device running 110. 
 Your flash problem is probaly caused by wrong memory settings in keil.
Launch nrfGo studio and find your device. Look at the memory spaces on the left. These addresses and sizes must correspond to your target options in keil. 
 Set "IROM1 Start" to "Application Address" from nrfgo. Set the "IROM1 Size" to the hex value of Application size shown in nrfgo. In my 110 it is 176 kB, or hex value 2C000 (176*1024->hex). 
 If this doesent work. make sure that you are using up-do-date versions of both keil, J-LINK and the nrf SDK.