nRF51822 + s130 2.0.0-7.alpha + bare minimum "bootloader" which starts app at 0x1B000 ?

[Alex Pristenskiy]

Hello.

I'm investigating how bootloader works (bare minimum), especially how it brings control to an application (already flashed at 0x1B000, s130 SoftDevice also present in flash).

I do the following:

1. Flash s130 2.0.0-7.aplha SoftDevice with nRFgo studio.

2. Flash simple BLE app example at address 0x1B000 (at this step if i reset nRF51822 module - app works fine!)

3. Flash minimal bootloader to 0x3C000 which purpose is only to run app at 0x1B000

The bootloader code is a copy&paste from nRF51422 (no examples for nRF51822 in SDK) bootloader code example - only minimum of code which starts application.

And bootloader fails to start an application - while calling sd_softdevice_vector_table_base_set() function it fails to SVC_Handler at 0x0003C1D2

Could you please tell me how to create bare minimum bootloader which only run application at 0x1B000 ?

Here is the code of minimum bootloader (185 lines of code): http://pastebin.com/kAZruUPp

Questions: if I have s130 SoftDevice stack flashed - should I initialize SoftDevice in bootloader OR bootloader may immediately start app at 0x1B000 (which will initialize SoftDevice and use BLE stack) ?

[Alex Pristenskiy]

Yahooooooooooooo!!!! Problem solved! :-)

I forgot to initialize SoftDevice vector table and thus call to sd_softdevice_vector_table_base_set() calls empty bootloader's SVC_Handler.

http://pastebin.com/H6VEymZg - working example of bare minimum bootloader which only starts application at 0x1B000

[Miguel]

Hello Alex, very nice post. I was having problems with the SDK DFU examples, none was working. But yours works well. How did you manage to perform a DFU with this code?