I noticed that the FTP application provided in the sample code is RAM-based. However, this will not work in my application since my chip will be out on the field and I want to do remote upgrade thru either FTP or HTTP. Is it possible to start the FTP session as another thread along with my HTTP server thread so I can upgrade the firmware remotely? If not, what is the recommended way to upload new firmware into the NS7520?
It is absolutely possible to do a field update, but the details depend on different things. What OS version are you using? I assume 6.0 and in that case, it also depends on how you build you application. I belive that the normal approach would be to use the bootloader and the image.bin. In this case you are actually running out of ram already. (you control this in the build configuration). If you are not using compression and is actually running out of flash you need to build a small ram image that you can run when downloading, I’m not sure if this is included in 6.0 but it was in previous version. You should also be aware that if you are planning to use FTP server and file system, you cannot use the example application but have to change the FTP server to handle this. This is also the case if you integrate web server and file system.