I am using LPC1788 controller but its 512KB flash memory is not enough. But I have enough external flash memory and accessible by the file system but not accessible in the compilation of the project. I wonder if it is possible create a library that will load from the file system into RAM in order to run. Best regards,
Leonardo F. Farah
You can configure the linking to store code or data in one memory region but for use in a different memory region.
So just as it's possible to get the compiler to store the code of a function in flash and have it copied into RAM before use, it's possible to have code linked for storage in external flash bus use in RAM. But you must make sure that the external memory is accessible before you call the CRTL init code that performs the initialization of all variables etc - so it's able to access and copy the flash code into RAM.
A function to run on RAM needs to be stored in the flash and then the initialization routines will copy it to the RAM. For this the IDE must be able to store the function in the flash memory which is not possible as it has a written algorithm that involves byte sequences at specific addresses and also because it is only available after starting the external memory controller. The idea would be that the main application can access a file in a file system stored in external flash, which will be loaded into memory and serve as a library of functions that can be called by the main application.
Note that you can write your own flash programming algorithm, which means that you can teach your IDE how to send parts of your program to the internal flash, and parts of the program to external flash.
But Keil's code that takes care of initializing RAM requires that the external flash is directly accessible (i.e. not as a file system but through a normal pointer), and that you have made sure that the startup file has initialized any external memory controller needed to reach the external flash.
Trying to implement dynamically loading of code means that you will have quite a lot of work to do, since you have no operating system with code loader running. And this route will also make it a nightmare to debug your code, since the debugger doesn't have support for any dynamically loaded code. And Keil most definitely aren't interested in introducing tool support for this since people would then try to abuse this method to get around code size limitations of evaluation or "lite" versions of the tools.
I certainly prefer that the IDE can do all the work because the debug would not be harmed. I will look for some documentation on how to implement my own algorithm for external flash programming and try to make its configuration.
These ARM development tools aren't going to support the kind of transparent overlaying system and debugging you want.
For DLL type applications you're going to have to decompose your project into individual components, and then build your own loader functions to pull in these DLLs and link to the functionality.
I finally finished writing the flash programming algorithm. Use the algorithm along with an .ini file that initializes the microcontroller registers to enable and configure external memory controller.
The ini file:
//*********************************************************************************************
/***********************************************************************/ /* FLASH.INI: Flash Initialization File */ /***********************************************************************/
//*** Use Configuration Wizard in Context Menu ***
FUNC void Setup (void) { int x, y, z;
_WDWORD(0x4002C138, 0x000000B1); // PINSEL_ConfigPin(2,14,1) _WDWORD(0x4002C13C, 0x000000B1); // PINSEL_ConfigPin(2,15,1)
y = 0x4002C180; z = 0x4002C200; for (x = 0; x < 32; x++) { _WDWORD(y, 0x000000B1); // PINSEL_ConfigPin(3,0,1) _WDWORD(z, 0x000000B1); // PINSEL_ConfigPin(4,0,1) y += 4; z += 4; }
_WDWORD(0x4002C280, 0x000000B1); // PINSEL_ConfigPin(5,0,1) _WDWORD(0x4002C284, 0x000000B1); // PINSEL_ConfigPin(5,1,1)
_WDWORD(0x400FC100, 0x00000001); // LPC_SC->EMCCLKSEL = 1
_WDWORD(0x400FC0C4, 0x04288FDE); // LPC_SC->PCONP = 0x04288FDE
_WDWORD(0x2009C000, 0x00000001); // LPC_EMC->Control = 1
_WDWORD(0x2009C200, 0x00000081); // LPC_EMC->StaticConfig0 = 0x81
_WDWORD(0x2009C204, 0x00000002); // LPC_EMC->StaticWaitWen0 = 2 _WDWORD(0x2009C208, 0x00000002); // LPC_EMC->StaticWaitOen0 = 2 _WDWORD(0x2009C20C, 0x0000001F); // LPC_EMC->StaticWaitRd0 = 0x1F _WDWORD(0x2009C210, 0x0000001F); // LPC_EMC->StaticWaitPage0 = 0x1F _WDWORD(0x2009C214, 0x0000001F); // LPC_EMC->StaticWaitWr0 = 0x1F _WDWORD(0x2009C218, 0x0000000F); // LPC_EMC->StaticWaitTurn0 = 0xF }
Setup(); // Setup for Flash
The firmware recording goes smoothly but I can not do debug. The following messages appear:
ULINK - Cortex-M Error Cannot access target. Shutting down debug session.
uVision Error: Could not load file 'D:\Projects\NOR Flash Teste.axf'. Debugger aborted !
This error happens with code:
const unsigned long teste __attribute__ ((at(0x80000000))) = 0x11223344;
and I dont´t define the area 0x80000000 with size 0x400000 in Target->Read/Only Memory Areas. After this error the debugger loses communication with microcontroller and I need to make a mass erase with bootloader.
If I define the area 0x80000000 with size 0x400000 in Target->Read/Only Memory Areas the compilator allocate part of program for the area and messages appear:
ULINK - Cortex-M Error Memory Mismatch! Address: 0x80000000 Value = 0x00 Expected = 0x1F
In both cases the flash memory was correct flashed. In the second case it seems that the debuguer can not see the flash memory, as if the ini file did not work in debug. I configured ini file for both the debug and for flashing so do not understand what's going on.
I finally made the debug to work. I had to turn off the " load application at startup" and do a Load %L in end of the .ini file. However, the IDE does not set breakpoints in external flash address ( 0x80000000 ) what I 'm trying to understand .
I finally made the debug to work. I had to turn off the " load application at startup" and do a Load %L in end of the .ini file. However, the IDE does not set breakpoints in external flash address ( 0x80000000 ). Apparently hardware breakpoints are limited to the first 1G memory from what I read in other forums.