RE: some problems about Integrating 2 application firmwares on 51822

ziv — Sat, 26 Apr 2014 03:34:05 GMT

newest test results shows that it's faults of the flash ease/write operations. The bootloader and the startup procedure represented above work both without problems. For reference if someone else need this information.

RE: some problems about Integrating 2 application firmwares on 51822

ziv — Tue, 11 Mar 2014 07:04:53 GMT

Thanks! I will study the code on github to get ideas. Maybe it's better to change the procedure of OTA to make it easy.

RE: some problems about Integrating 2 application firmwares on 51822

Ole Morten — Mon, 10 Mar 2014 13:48:44 GMT

What you want is not easy to do, and is not directly supported by the softdevice. Getting this to work requires that you fully understand how the softdevice works, and how interrupts are forwarded. I'd therefore recommend you to read the appendix of the nRF51 Reference Manual very thoroughly, as well as the S110 SoftDevice specification.

Currently, the softdevice supports having one application and one bootloader. If a bootloader address is written to the address 0x10001014 in UICR, the softdevice will jump to the reset handler at this address when power is applied to the chip, and the softdevice has finished its own initialization. All interrupts will also be forwarded to the bootloader at this address. The bootloader can then determine whether there is a valid application in the flash, and if there is, call the sd_softdevice_forward_to_application() function, and then jump to the application's reset handler. After having called sd_softdevice_forward_to_application(), all interrupts will be forwarded to whatever handler is located at address 0x14000, and hence the application at this address will receive all interrupts, no matter which application's main function was called.

Therefore, I can't see any other way of achieving what you want than to locate your own bootloader at 0x14000, not use the softdevice bootloader API and instead do interrupt forwarding on your own. This should be perfectly possible technically, but it is not trivial to get right, and it will also introduce some additional interrupt latency. The bootloader that is public here does this, but it's written for gcc, and it also has a pretty significant bug that you need to work around or fix if you're considering using it.