Digi ME-S and -C

The answer is probably no but we have various units here of -C and -S and as I understand it is the -C is for hosting code we have developed and the -S already has Digi’s implementation of web/serial/tcp/ftp etc…

I have also read somewhere that the two devices are actually identical and Digi just program them with the appropriate code to meet orders.

If they are the same is it then possible to reprogram the -S devices with our code ?
It would save a lot of hassle as otherwise we will have to mod a lot of boards.



The way I was told:

  1. The -S has the bootstrap that contains the “Diagnostic” emergency recovery, similarly to the original ME. If you don’t have pin 19 pulled down on boot, it works just like a -C.

  2. The -C has only a tiny bootstrap that just launches the program.

Neither of them come pre-programmed (unless you get them OEMed), but there are several levels of kits that give you certain things:

A. Integration Kit - This has a group of prewritten programs similar to what you mention that may be loaded onto the ME. This is -C only.

B. Development Kit - This has the source code and the compiler to develop your own code - either -S or -C.

C. There is a 3rd kit which I don’t know anything about.

You can get a development board with any of these that comes with a special ME that has a JTAG port which may be used for remote diagnostics. If you use the -C modules (which is what Digi sends you even if you order the -S), DO THIS. There is a good chance that you will not have a functioning FTP or similar reprogramming capibility, and a -C is useless unless you have something to do this in your program. The JTAG lets you do an emergency recovery.


Hi Erik
Thanks for the info. I am using the development kit with JTAG to write an application using NET-OS 7.

The reason why I asked the question is that we have been using the -S units for some time now as only basic TCP -> serial was needed. Now we are requireing some protocol translation so need to develop our own code.

I have tried to program a -S device with the compiled image but there must be some kind of check to detect whether it’s a Digi image as it fails.

It programs fine into a -C. It would just be nice to be able to re-use all the -S modules we have.

I will give it a go with either floating pin 19 or pulling it high.

Will post results.

Thanks again


The Pin 19 soulution calls up a specialized interface on boot to allow the reprogramming of the module in case your program cannot reprogram itself (eg: you forgot the FTP code or something like that). It doesn’t affect the normal module boot.

What you need is the -S kit that modifies the BSP to work with the -S modules. I was told by Digi that it exists (back when Cameron was doing support for the ME), but I haven’t seen one myself. Digi support is really chary about releasing -S information for some reason. Give them a support call, they should just send you the ME-S kit.

Note that I am basing all this on NetOS 6.x. Maybe they don’t support -S modules with NetOS 7.x.


Erik is right about the lack of support for the -S modules with the NET+OS 7.x development kit. The “LSK” for NET+OS 6.0x defined a new platform type to work with -S modules which was useful for several early customers of the ME. It may be ported forward to 6.3, but is unlikely to be fully supported on 7.x. Tech Support can provide the LSK for customers who need/want it, but there are limitations when using the -S modules for NET+OS development (e.g., your code won’t seamlessly migrate to other platforms).

Unfortunately there are no plans at this time for support of -S modules in current or future releases of NET+OS going forward. It is only possible at this time to use -C modules with currently supported NET+OS versions.