Lpc2000

Charles and Klaus,

a little update on CAN and a few clarifications.
The term FullCAN and BasicCAN seem to be a little mixed with assumption 
was the one or the other does / does not do.
The FullCAN mode is still not operational on the current CAN devices 
such as LPC21x9, LPC2194 and LPC229x but the redesign has started, 
can't tell you yet for sure when the bug-fixed devices will be on the 
market but my best guess is end of Q4 this year.

FILTERING:
The difference between FullCAN (FC) and our other CAN mode, which I 
like to call Extended CAN (EC) is filtering but not as you expect. The 
EC offers MUCH more fitlering options than the FC mode. Literally 
hundreds of messages can be filtered from a stream of ongoing CAN 
messages without receiving a single message you are not interested in. 

OFFLOADING RECEIVE REGISTER:
This is the real difference between FC and EC. In FC mode, the message 
will automatically be transferred into a dedicated message buffer, in 
EC mode, your software will have to take care of moving the (filtered) 
message to its final destination before the next complete message has 
been received. As Charles mentioned this is not a high CPU load for an 
ARM running at ?? MHz. 

29-BIT IDENTIFIERS:
FC as implemented does not and will not support 29-bit identifiers, 
however our EC mode does fully support 29-bit identifiers. 

CAN PERFORMANCE:
You can definitely run all (max 4) CAN interfaces at max speed of 1 
Mbit and even receive every single message with 100% busload and still 
have processing power left to do something else. So there is no impact 
on CAN performance because of fixing the FC mode. 

Hope this helps and gives some additional information, Robert


--- In lpc2000@yahoogroups.com, "embeddedjanitor" <manningc2@a...> 
wrote:
> --- In lpc2000@yahoogroups.com, "Klaus" <klaus276@y...> wrote:
> > Is it correct, that the FullCANmode is not yet operational? When 
> will
> > it be fixed? What will be the expected performance advantage of the
> > FullCANmode compared to the BasicCANmode?
> 
> Just do all your filtering etc in software. This does not add any 
real 
> loading to an ARM7.
> 
> Unless you need absolutely every % of the CPU I doubt you'd notice 
the 
> difference between FULL and Basic modes.