Snow town!

I just wanted to share with you some pictures of my town during the unusual and unexpected snow…

16C950 UART 9-bit and custom baud rates support for Linux

Last friday I found myself patching the Linux kernel sources to be able to add custom baud rates support for 16C950 UART cards. I needed to communicate, via a serial port, with one of the devices built by the hardware guys at work. Unfortunately, a non-standard baud rate and 9-bits were needed.

The Sealevel Ultra COMM+422 PCI card we are using is already provided with a patch that adds 9-bit support. However, I was not able to found how to change the baud rate to a non-standard one.

Following the 9-bit patch approach, I added extra requests to ioctl in order to modify the 16C950 registers needed to achieve custom baud rates. Here is the list of added extra ioctl requests (also the 9-bit ones) with the necessary parameters and updated/accessed 16C950 registers:

Request	Parameters	16C950 registers	Description
TIOC9BITGET	out: integer	NMR	Get current 9-bit status
TIOC9BITSET		NMR	Enable 9-bit support
TIOC9BITCLR		NMR	Disable 9-bit support
TIOCPRESCALERGET	out: integer	EFR, MCR	Get prescaler status
TIOCPRESCALERSET		EFR, MCR	Enable prescaler
TIOCPRESCALERCLR		EFR, MCR	Disable prescaler
TIOCDIVLATCHGET	out: integer	LCR, DLL/DLM	Get divisor latch register
TIOCDIVLATCHSET	in: integer	LCR, DLL/DLM	Set divisor latch register
TIOCSAMPLINGCLKGET	out: integer	TCR	Get sampling clock
TIOCSAMPLINGCLKSET	in: integer	TCR	Set sampling clock
TIOCPRESCALERCLKGET	out: integer	CPR	Get prescaler clock
TIOCPRESCALERCLKSET	in: integer	CPR	Set prescaler clock

I’m not sure if this is the best way to do it, but it works. So, if you need 9-bit and custom baud rates support, apply one the following patches to the kernel (I have aslo updated the Sealevel patch for older and newer kernels than the one provided):

9-bit	2.6.24	2.6.26	2.6.31	2.6.32
9-bit and baud rate	2.6.24	2.6.26	2.6.31	2.6.32

I am not responsible for any damage that these patches can cause to your hardware. No warranty is provided, so use them at your own risk.

SCEW 1.1.1 released

Finally, character escaping has been added to SCEW. This new release only features this and fixes output on Windows console for UTF-16 characters.

Stay tuned, major BitPacket updates come next!

Happy hacking!

SCEW 1.1.0 released

I’m pleased to announce SCEW 1.1.0. This is a minor release including two minor bug fixes and improvements for XML tree and element comparisons. Users can now provide their own XML tree and element comparison hooks.

Check out the release notes.

Happy hacking!

SCEW 1.0.0 released

I’m pleased to announce SCEW 1.0.0. It has been a long time since the last release in May 2004.

This new release includes a lot of improvements: unit tests, homogenized API, a lot of new functions, support for custom I/O sources, documentation updates, Windows support improved and many others.

Please, have a look at the changes for more details.

Savannah mirrors are being updated, so until then use the no-redirected download.

As usual, bugs, comments, criticisms, etc. are more than welcome.

Happy hacking!