LPC2000 CAN project

Greetings!

I have just join this group as it might be a good place to have some chat
about NXP projects. 
I want to make OBD2 scanner using one of the LPC chips. Now, I dont have
any experience with CAN protocol, but I read about it and kind of
understand how it works. What is not clear is if filtering of the messages
is done by MCU or CAN controller ?
I found most of implementations is around MCP2515 CAN controller and
MCP2551 transceiver. 
I dont really know if theres a benefit of using LPC CAN controller over
MCP2515, or just stick with any LPC and use the SPI for that? As MCP have
2 or 3 I/O buffers, is that enough for fast communication ? 
What I want to achieve is to read some of the sensors from the car CAN and
show it on a small TFT display. 
Suggestions? Should I use LPC with CAN or stick with MCP ? Implications
are that i need to make new PCB for LPC with CAN, and for MCP i can just
order a board and connect it to SPI.



---------------------------------------
Posted through http://www.EmbeddedRelated.com

"gossamer" wrote:

>I want to make OBD2 scanner using one of the LPC chips. 
...
>Suggestions? Should I use LPC with CAN or stick with MCP ? Implications
>are that i need to make new PCB for LPC with CAN, and for MCP i can just
>order a board and connect it to SPI.

The LPC11C24 has a built-in CAN controller and CAN bus drivers.
Embedded Artists had a demo board with this chip, may be others.

R.W.

gossamer wrote:
> Greetings!
>
> I have just join this group as it might be a good place to have some chat
> about NXP projects.
> I want to make OBD2 scanner using one of the LPC chips. Now, I dont have
> any experience with CAN protocol, but I read about it and kind of
> understand how it works.

It may be worth getting a Komodo USB CAN interface and using that a bit
to learn. They have a library that allows programming against the
device, or you can just use their GUI for capture.

I have one connected to a Cubie board in this way. I'm sure a RasPi
or Beaglebone Black would work as well, or you can just connect
it to a Windows or Linux workstation/laptop/what have you.

> What is not clear is if filtering of the messages
> is done by MCU or CAN controller ?

Figure 4.2 on page 25 here:
http://ww1.microchip.com/downloads/en/DeviceDoc/21801G.pdf
has some detail.

> I found most of implementations is around MCP2515 CAN controller and
> MCP2551 transceiver.
> I dont really know if theres a benefit of using LPC CAN controller over
> MCP2515, or just stick with any LPC and use the SPI for that? As MCP have
> 2 or 3 I/O buffers, is that enough for fast communication ?
> What I want to achieve is to read some of the sensors from the car CAN and
> show it on a small TFT display.
> Suggestions? Should I use LPC with CAN or stick with MCP ? Implications
> are that i need to make new PCB for LPC with CAN, and for MCP i can just
> order a board and connect it to SPI.
>
>
>
> ---------------------------------------
> Posted through http://www.EmbeddedRelated.com
>

-- 
Les Cargill

On Thursday, September 10, 2015 at 2:03:37 PM UTC-4, Roberto Waltman wrote:
> "gossamer" wrote:
> 
> >I want to make OBD2 scanner using one of the LPC chips. 
> ...
> >Suggestions? Should I use LPC with CAN or stick with MCP ? Implications
> >are that i need to make new PCB for LPC with CAN, and for MCP i can just
> >order a board and connect it to SPI.
> 
> The LPC11C24 has a built-in CAN controller and CAN bus drivers.
> Embedded Artists had a demo board with this chip, may be others.
> 
> R.W.

To echo what Roberto said: LPC11Cxx has an excellent CAN interface
with built-in drivers (drivers in ROM) - quite easy to use.
You'll want to get yourself a CAN book and study; CAN is quite
different from other communication schemes.

IAR also makes an LPC11 starter/devel board which I used to get up
to speed, before I designed a couple boards using LPC11C22.
Provided free CodeRed studio (now owned by NXP) was quite good as well.

Hope that helps!
Best Regards, Dave

Roberto Waltman wrote:

> "gossamer" wrote:
> 
>>I want to make OBD2 scanner using one of the LPC chips.
> ...
>>Suggestions? Should I use LPC with CAN or stick with MCP ? Implications
>>are that i need to make new PCB for LPC with CAN, and for MCP i can just
>>order a board and connect it to SPI.
> 
> The LPC11C24 has a built-in CAN controller and CAN bus drivers.
> Embedded Artists had a demo board with this chip, may be others.
> 
> R.W.


using a CAN module internally connected to the controllers peripheral bus is 
always a better solution compared with a CAN controller connected via SPI.
Hundreds of controllers with integrated CAN are available by different 
manufacturers:
http://www.can-wiki.info/doku.php?id=controllers:main

You should take care to have a migration path to CAN-FD.

 Heinz

Heinz-J�rgen Oertel wrote:

>Roberto Waltman wrote:
...
>> The LPC11C24 has a built-in CAN controller and CAN bus drivers.
>> Embedded Artists had a demo board with this chip, may be others.
>
>
>Hundreds of controllers with integrated CAN are available by different 
>manufacturers:
>http://www.can-wiki.info/doku.php?id=controllers:main

Correct, but most do not have bus drivers. (Electrical buffers, not
software.)

R.W.

Roberto Waltman wrote:

> Heinz-J�rgen Oertel wrote:
> 
>>Roberto Waltman wrote:
> ...
>>> The LPC11C24 has a built-in CAN controller and CAN bus drivers.
>>> Embedded Artists had a demo board with this chip, may be others.
>>
>>
>>Hundreds of controllers with integrated CAN are available by different
>>manufacturers:
>>http://www.can-wiki.info/doku.php?id=controllers:main
> 
> Correct, but most do not have bus drivers. (Electrical buffers, not
> software.)
> 
> R.W.

You are correct. The LPC11C22 and LPC11C24 parts include an on-chip, high-
speed CAN transceiver. I assume it is a dual die implementation.

 Heinz