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FreeRTOS + UDP + TCP

Posted by gwesp on October 12, 2017

Hi,

We're trying to add TCP and UDP to a project. We noticed that there are huge differences in files that are required for both, e.g. FreeRTOS_DHCP.c, including differing function signatures.

How can we resolve this situation? Is the combination of UDP and TCP supported or can you use only one of both?

We're evaluating FreeRTOS version 9.0.0.

Thanks and kind regards --Gerhard Wesp KISS Technologies GmbH


FreeRTOS + UDP + TCP

Posted by rtel on October 12, 2017

The FreeRTOS+TCP stack available from the labs download (or the FreeRTOS SVN repository) has both TCP and UDP. Take a look at the features list and API in the tables at the bottom of the following page: http://www.freertos.org/FreeRTOS-Plus/FreeRTOSPlusTCP/index.html


FreeRTOS + UDP + TCP

Posted by gwesp on October 12, 2017

Thanks for your quick reply. I see I wasn't specific enough in my description.

We're currently targetting the LPC1830 Xplorer board. For this, we use the example from FreeRTOS-Plus/Demo/FreeRTOSPlusUDPandCLILPC1830GCC from FreeRTOSv9.0.0 . This works very well, but it doesn't include TCP.

Now when we add the FreeRTOS+TCP stack (I downloaded version 160919FreeRTOSLabs) you mentioned, I see now that it does indeed include UDP as well. Still, we cannot use it for the LPC1830 example above because some files are duplicate and have huge diffs. One example is:

diff ./160919FreeRTOSLabs/FreeRTOS-Plus/Source/FreeRTOS-Plus-TCP/FreeRTOSDHCP.c ./FreeRTOSv9.0.0/FreeRTOS-Plus/Source/FreeRTOS-Plus-UDP/FreeRTOSDHCP.c [ --> results in ca 1000 diff lines, including changed function prototypes ]

The question is how to resolve these 'merge conflicts'. Any suggestions would be greatly appreciated.

Actually, for the time being we'd be fine with TCP alone but we need it on the LPC1830.

Thanks and kind regards --Gerhard Wesp KISS Technologies GmbH


FreeRTOS + UDP + TCP

Posted by rtel on October 12, 2017

The UDP and TCP products are different (or, at least, the TCP product is an extension of the UDP product that is now different) - remove all the FreeRTOS+UDP code and add the FreeRTOS+TCP code - then you will have both UDP and TCP.


FreeRTOS + UDP + TCP

Posted by heinbali01 on October 12, 2017

Hi Gerhard, once upon a time, there was FreeRTOS_Plus_UDP. This library could only do UDP, DHCP and ICMP(echo). A couple of years ago, this stack was re-engineered and extended with a few more protocols, and it was called renamed to FreeRTOS+TCP. The name +TCP is possibly misleading, it should have been called FreeRTOS+UDP+TCP+DHCP+ICMP+FTP+HTTP+NBNS+LLMNR+etc :-)

In other words, what you should do is forget about the FreeRTOS_Plus_UDP, and work with FreeRTOS+TCP.

The two stack use the same principles, and they have the same kind of interface. Both stacks use a single IP-task that does all the work.

When working with FreeRTOS+TCP, start simple. Disable DHCP at first and give your device a fixed IP address. Try to ping it, and when that works, try DHCP and other protocols.

When you have questions, please post them here, in this thread.


FreeRTOS + UDP + TCP

Posted by gwesp on October 13, 2017

Thanks Hein,

that sounds like a plan. Since the API closely resembles the BSD sockets, I suppose we can do what RTE suggested and just replace-merge the FreeRTOS+TCP files into the LPC1830 example.

Best --Gerhard


FreeRTOS + UDP + TCP

Posted by heinbali01 on October 13, 2017

just replace-merge the FreeRTOS+TCP files into the LPC1830 example

Right, remove the entire UDP stack, and include the +TCP stack.

I will attach the current driver for LPC18 here below ( see LPC18xx_2017_oct.zip )

It is a zero-copy driver, so please add the following to your FreeRTOSIPConfig.h

~~~ #define ipconfigZEROCOPYRXDRIVER 1 #define ipconfigZEROCOPYTXDRIVER 1 ~~~

A few parameters to tune are the following:

~~~ #define configNUMRXDESCRIPTORS 6 #define configNUMTXDESCRIPTORS 4 #define ipconfigNUMNETWORKBUFFER_DESCRIPTORS 15 ~~~

And later on, you may want to tune some TCP parameters, as describer here

The "quad" flash in the LPC18 that I used was a bit slow, and I placed some frequently-used functions in RAM:

~~~ #ifndef configPLACEINSECTIONRAM #define configPLACEINSECTIONRAM attribute ((section(".ramfunc"))) #endif

/* Move func() to RAM: */
configPLACE_IN_SECTION_RAM void func()
{
}

~~~

The .LD file contains the .ramfunc entry, in the RamLoc96 section:

~~~ /* Main DATA section (RamLoc96) / .data : ALIGN(4) { FILL(0xff) _data = . ; *(vtable) *(.ramfunc) (.data) . = ALIGN(4) ; edata = . ; } > RamLoc96 AT>SPIFI4MB ~~~

If you have a fast flash, there is no need to move code to RAM.

Good luck!

Attachments

LPC18xx_2017_oct.zip (10192 bytes)

FreeRTOS + UDP + TCP

Posted by gwesp on October 13, 2017

Thanks a lot, Hein! We'll definitely check that out. From our UDP example it didn't appear that we're particularly CPU bound, but it's always good to have options.

Best --Gerhard


FreeRTOS + UDP + TCP

Posted by heinbali01 on October 15, 2017

From our UDP example it didn't appear that we're particularly CPU bound

As you probably know, the Ethernet layer needs two components:

1) Ethernet Media Access Controller (EMAC) 2) Ethernet PHY

The EMAC is often an internal peripheral of the CPU. A PHY is an external component. The EMAC and PHY communicate through a high-speed bus, MDIO or a newer protocol.

Both FreeRTOSPlusUDP as well as FreeRTOS+TCP need a driver for these two components. This driver exists of a xxx/NetworkInterface.c file and some (modified) drivers provided by the chip manufacturer.

I recently started to split-up the PHY-driver and make a generic driver that should work on all boards. As soon as it is well-tested, I will publish it here on this forum.


FreeRTOS + UDP + TCP

Posted by gwesp on October 24, 2017

OK, let us know when you have any updates. We were able to integrate your network driver into our project with some minor modifications (ChipENETInit() function takes two arguments) and now working on a driver for our PHY (DP83822 on our final target hardware). Thanks a lot.


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