mattcro

Hi All, I've started experimenting with N+2 as the possible basis for a commercial project that was shelved a while ago and for which we originally looked at the N+.

One of the requirements is remote upgrading of the firmware/application, preferably from a file on the SD card (ultimately over the network from a central server that the units report to). This should include the firmware/CLR so I guess dynamic assembly loading is not a complete solution. We want to be able to deal with a missing SD card and survive multiple power cycles so even if we leave out firmware updates, loading assemblies from SD every reboot is not ideal.

I'm trying to get my head around the requirements for DFU over UART, as we will likely have an 8-bit micro as an I/O expander which could do the job of bootload host provided that the 2 chips can share the SD card (if one set of pins can be tristated while the other accesses the card). It'll obviously be slower than over USB, but will hopefully only be needed infrequently.

It looks like the STM32 can bootload from USART1 or USART3, but these pins are used by the on-board switch and USB. USART3 looks promising, if the pin is isolated from the switch and maybe also PC14.

Has anybody else used this kind of set-up for remote or in-field updating? There are various posts about dynamic assemblies, but I guess most Netduinos are either in a controlled environment or it's feasible to do upgrades by plugging into a PC and using VS or MFDeploy.

Any info/pointers appreciated!

Matt