Want to Know Details of LPC2148 and RTOSs

[nikhillife11]

Thanks a Lot BigDog,

and I want to know one more thing if you can spare your time. Actually I wanted to know whether I can port Linux in ARM LPC2148. Is it possible and can you guide me on the same.

Thanks

Nikhil

 

[bigdogguru]

Re: Want to know details of LPC2148 PLL

Not unless you're a miracle worker.

The first problem is the LPC2148 does not have a MMU, but there are distros which run on MMU-less ARMs like µCLinux.

However, the miracle required would be, how to squeeze a Linux kernel into only 40kB of SRAM considering LPC2148 does not provide an external memory bus.



There are several RTOSs which could be successfully implemented on the LPC2148:

eCOS

FreeRTOS

µC/OS-II and µC/OS-III


To successfully run Linux on a NXP LPC ARM variant you would have to move up to something like a LPC2478:

Embedded Artists' LPC2478-32 Developer's Kit

Hope the info helps,

BigDog

 

[nikhillife11]

Re: Want to know details of LPC2148 PLL

Hey BigDog, Your always been a lot of help and I am actually reading the book for UCOS II by its author. But I am not understanding how to use those Macros in my code. I am using Keil ARM 4 eval version. Do you have any simple examples for LPC2148 and UCOSII. So that i can grow step by step. I googled out some code. But they are Huge and Confusing. So can You help me out with Something simpler

Thanks

Nikhil

 

[vishnuksumithran]

Hey nikhillife11 , I am running FreeRTOS on LPC2148 board.If you are interested you can find necessary info at my blog @ VL@BZ BLOG - Home . This port works with GNU winarm toolchain and not with Keil compiler (not tried with keil). I have created 2 tasks just to test the rtos working. please go through the files and edit 'main.c' file according to ur specification.

 

[bigdogguru]

There doesn't seem to be a lot of tutorials available online concerning uC/OS-II, but after searching the internet I finally found a fairly decent tutorial on uC/OS-II.

I have attached the PDFs as a zip file. There are five PDFs, Chapters 1 to 3 seem to be fairly helpful.

Hope you find them helpful.

BigDog

 

[nikhillife11]

Hey bigDog,

Thanks again...i will go through and get back to you. In the meantime,I have one more question. Can i connect a external RAM and Flash of higher memory to LPC2148 such that i can load the Linux kernel into flash and then with help of LPC2148 can boot from that flash. Is this scenario possible....

I know it doesn't have a MMU neither any provision for memory mapping..But is there still any other option.
Thanks..TC

Nikhil

 

[bigdogguru]

Unfortunately most ARM7s do not have an external memory bus designed to provide direct addressing to external SRAM or FLASH.

The LPC series of ARMs refer to this external memory bus as an External Memory Controller (EMC), the LPC2377 and LPC2378 are exceptions to this rule:

External memory controller
The LPC2377/78 EMC is an ARM PrimeCell MultiPort Memory Controller peripheral offering support for
asynchronous static memory devices such as RAM, ROM, and flash. In addition, it can be used as an
interface with off-chip memory-mapped devices and peripherals. The EMC is an Advanced
Microcontroller Bus Architecture (AMBA) compliant
peripheral.

The LPC2148, as far as I know, does not offer this feature. Therefore you are stuck with the onboard FLASH and SRAM for program storage and execution. You can implement a SD/MMC flash card interface which would give you additional data storage, but not program storage.

BigDog

 

[nikhillife11]

Hello BigDogguru,

Your the best help I have got so far. Thanks for everything mate. You rock. I am just going through the zip files you have given. Will try somethings out and will get back to you

Regards

Nikhil

 

[lakshmi_priya]

Hi bigdogguru,

the rar file requiring password..

 

[bigdogguru]

the rar file requiring password..

What RAR file?

I have only uploaded a ZIP and it is not password protected.

BigDog

 

[alexan_e]

There is a rar inside the zip

 

[bigdogguru]

There is a rar inside the zip

Alright, I see what you are referring to now.

Unfortunately, I can not find the password, therefore I have removed the RAR from the ZIP file.

However, you can download µC/OS -II source for many architectures from the following site:

Micrium Download µC/OS Source Code

And various µC/OS -II Ports from the following:

Micrium Ports

I would also recommend the following text:

MicroC OS II: The Real Time Kernel (With CD-ROM)

Which has all the source files, several ports and examples used in the tutorials.

BigDog