XON/XOFF flow control

I am using a fastrack as simple modem and have no free pins to control the flow of data by means of hardware.
Is there any way to implement an XON/XOFF flow control?.

I have similar usage and require the same solution. Is there access to the driver source code so we can expand the flow control options to include XON/XOFF?


The ADL (OpenAT) OpenDevice API appears to support software flow control.

You might be able to write a small app to load into your fastrack to manage the data flows on UART1. I doubt that you’ll get a driver change from SiWi quickly.

Have a look at section 4.1 of the ADL User Guide for Open AT.

ciao, Dave

David, thank you for your encouraging reply.

I couldn’t find the “ADL User Guide for Open AT” anywhere in my documentation set, nor via searches in the resource section of SiWi’s web-site.

Please be kind enough to point me towards it.
Sorry for being a dumbass here.


Don’t feel bad about not being able to find the doco. SiWi have buried it deep within the Developer Studio bundle and expect you to access it from within DS. There’s been a number of discussions about the problems with this method, but nothing has changed.

The first thing I do when I install DS is to go hunting for the doco and put the PDF’s somewhere useful (so I can have DS on one monitor, and the doco on another!).

You’ll need to install Developer Studio. My version is installed into C:\OpenAT-DS-2.2.1 - your location may vary.

Then, go looking for the following directory under the base install (all one line):

Embedded Software\com.wavecom.openat.ide.spm.lib.os.model.\resources\doc

Note that the ‘6.52.xxxx’ is the firmware version - this changes from release to release.

In the ‘Doc’ folder, you should find the ‘ADL_User_Guide.pdf’, which is the document I referred to above. There will be a version of this for each different version of the firmware - it’s important to read the right version for the firmware you are using as there are subtle changes between versions.

Note that the AT commands guide is available in a similar manner - look for the ‘xxx.fw.model.xxx’ directories in the same ;Embedded Software’ directory.

Hope this helps somewhat.

ciao, Dave

Yes David, thank you, it helps a bloody lot. I’ve found it and have now got some reading to do. What a stupid place to hide this essential document.

Why aren’t these guys listening? This is a modem ostensibly for embedded applications, why wouldn’t we want a minimalistic interface, where resources are finite. The specification defines XON/XOFF flow control, so why are these guys so lazy about implementing it. The USB Uart is useless for embedded applications, but the RS232 is one of the oldest and simplest interfaces, yet its support is relegated in favour of latter-day more sophisticated options.

I did a lot of digging before I settled on this product, little did I realise I would be scuppered at this level.

Thank you again for your prompt response.

And finding it on the web isn’t much easier.



Similarly, I do a Windows search for *.pdf, then make shortcuts in an easily-accessible place.

I also make shortcuts of relevant docs in my Project folders.

Indeed. :smiley: