[En-Nut-Discussion] New UART driver, 9 Bit Drivers

[Brett Abbott]

Harald

FYI.  The 9 bit code is still in use and appears very stable.

For memory optimisation, I was about to modify the 9 bit drivers to use 
HeapAlloc to create a structure which holds the additional IFSTREAM 
buffers required for 9 bit.  This would be created only when 9bit is 
selected using the set number of bits option (ioctrl).  This would 
reduce the memory impact on solutions that dont need the 9 bit 
functionality by reducing the size of IFSTREAM and avoiding the need to 
recompile code that use ifstream.h.

Also, In a lesser way, I find it annoying to have to recompile the 
library code if using the 9bit uart feature, to the point where I use 
the 9bit code for 8 bit apps too!  To address this I was considering 
creating new devices...  devUart0nine and devUart1nine (or some such 
name).  These two changes together would allow developers to select the 
9 bit option simply at NutRegisterDevice time.  The advantages here 
would include avoiding the need to  use compiler flags and recompile the 
libaries.  Single c source for uart's could be retained with the c 
source being the same for both versions but setting the  9 bit flag 
sepending on which device is being built.  I am uncertain on whether 
this would increase the libary base or not.  Disadvantages include 
having two uart libraries (not ideal)

In reflection, I favour the heap alloc of the 9bit buffers as required 
but retaining a single 9 bit Uart device.

What are your thoughts?  I could make these changes to your new code.  
Either way, these changes or not, Im extremely happy to be using 9 bit 
code from a standard Nutos release and are happy to help test/enhance 
/support as requried.

Thanks
Brett


-- 
-----------------------------------------------------------------
Brett Abbott, Managing Director, Digital Telemetry Limited
Email: Brett.Abbott at digital-telemetry.com
PO Box 24 036 Manners Street, Wellington, New Zealand
Phone +64 (4) 5666-860  Mobile +64 (21) 656-144
------------------- Commercial in confidence --------------------