CCS2.2和CCS3.1在读写GEL文件上的区别之二

下面具体谈一下GEL文件的执行过程。使用CCSStudio Setup工具，可以为在系统配置中的每一个处理器指定一个启动GEL文 件。当CCSStudio启动时，GEL文 件加载到PC机的内存中，由CCS根据加载的GEL文件对目标板进行初始化。在CCS2.2中，主机和目标板的初始化工作都在GEL文件的Startup()函数中执行，而CCS2.2必须在打开时就会连接目标板同时进行初始化。但是对于支持Connect/Disconnect的CCSStudio例如CCS3.1，打开后目标板并没有被自动连接，这样的GEL文件中的初始化程序并没有正确执行，因为CCSStudio启动时和目标处理器是断开的。当Startup()函数试图访问目标处理器时会出错。因此在CCS3.1中需要回调函数来重新执行初始化。下面可以将SEEDDM642.gel和EVMDM642.gel做一个对比。

首先是SEEDDM642.gel中的StartUp()

StartUp() { setup_memory_map(); GEL_Reset(); init_emif(); }

EVMDM642.gel中的StartUp()

 StartUp() { setup_memory_map(); /*------------------------------------------------------*/ /* Uncomment the OnTargetConnect() call for CCS 2.X */ /* support. */ /* */ /* */ /*------------------------------------------------------*/ //OnTargetConnect(); }

从这个函数的对比就可以看到前一个在StartUp()中就已经完成了GEL和emif的初始化工作，而在后一个中就没有，这一点和前面说的软件打开时目标板的连接方式刚好一致。

因此在CCS3.1的gel文件中就多了这样一段函数：

OnTargetConnect() { /*------------------------------------------------------*/ /* GEL_Reset() is used to deal with the worst case */ /* senario of unknown target state. If for some reason */ /* a reset is not desired upon target connection, */ /* GEL_Reset() may be removed and replaced with */ /* something "less brutal" like a cache initialization */ /* function. */ /*------------------------------------------------------*/ //GEL_Reset(); init_emif(); GEL_TextOut("GEL StartUp Complete./n"); }

即在目标板连接的时候进行初始化操作，由此就可以理解为什么前面弹出的警告了，将SEEDDM642.gel对应的部分修改后在运行警告消失，即在软件打开时不对芯片初始化，改在芯片连接时进行。

    同样可以看一下gel文件中的其他函数：

/*--------------------------------------------------------------*/ /* OnReset() */ /* This function is called by CCS when you do Debug->Resest. */ /* The goal is to put the C6x into a known good state with */ /* respect to cache, edma and interrupts. */ /*--------------------------------------------------------------*/ OnReset( int nErrorCode ) { init_emif(); } /*--------------------------------------------------------------*/ /* OnPreFileLoaded() */ /* This function is called automatically when the 'Load Program'*/ /* Menu item is selected. */ /*--------------------------------------------------------------*/ OnPreFileLoaded() { /*------------------------------------------------------*/ /* GEL_Reset() is used to deal with the worst case */ /* senario of unknown target state. If for some reason */ /* a reset is not desired upon target connection, */ /* GEL_Reset() may be removed and replaced with */ /* something "less brutal" like a cache initialization */ /* function. */ /*------------------------------------------------------*/ //GEL_Reset(); flush_cache(); IER = 0; IFR = 0; init_emif(); } /*--------------------------------------------------------------*/ /* OnRestart() */ /* This function is called by CCS when you do Debug->Restart. */ /* The goal is to put the C6x into a known good state with */ /* respect to cache, edma and interrupts. */ /* Failure to do this can cause problems when you restart and */ /* run your application code multiple times. This is different */ /* then OnPreFileLoaded() which will do a GEL_Reset() to get the*/ /* C6x into a known good state. */ /*--------------------------------------------------------------*/ OnRestart( int nErrorCode ) { /*------------------------------------------------------*/ /* Turn off L2 for all EMIFA CE spaces. App should */ /* manage these for coherancy in the application. */ /* GEL_TextOut("Turn off cache segment/n"); */ /*------------------------------------------------------*/ *(int*)0x01848200 = 0; // MAR0 *(int*)0x01848204 = 0; // MAR1 *(int*)0x01848208 = 0; // MAR2 *(int*)0x0184820c = 0; // MAR3 /*------------------------------------------------------*/ /* Disable EDMA events and interrupts and clear any */ /* pending events. */ /* GEL_TextOut("Disable EDMA event/n"); */ /*------------------------------------------------------*/ *(int*)0x01A0FFA8 = 0; // CIERH *(int*)0x01A0FFB4 = 0; // EERH *(int*)0x01A0FFB8 = 0XFFFFFFFF; // ECRH *(int*)0x01A0FFE8 = 0; // CIERL *(int*)0x01A0FFF4 = 0; // EERL *(int*)0x01A0FFF8 = 0xFFFFFFFF; // ECRL /* Disable other interrupts */ IER = 0; IFR = 0; }

由此可以更深刻的了解gel文件的作用和两个版本的区别了。