Startup.a51

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Read-Only Author Mohammad Adel Posted 15-Apr-2004 23:52 GMT Toolset C51	Startup.a51 Mohammad Adel Is it always important to include the file "startup.a51"? Should anything else be included for it to work properly? Thanks

Read-Only Author Raj Shetgar Posted 16-Apr-2004 05:23 GMT Toolset C51	RE: Startup.a51 Raj Shetgar Hi, http://www.keil.com/support/docs/1296.htm Rgds Raj Shetgar

Read-Only Author Eduard Jadron Posted 16-Apr-2004 07:51 GMT Toolset C51	RE: Startup.a51 Eduard Jadron Yes it is primary init for 51.

Read-Only Author Mohammad Adel Posted 16-Apr-2004 13:15 GMT Toolset C51	RE: Startup.a51 Mohammad Adel Is there some detailed explanation of startup.a51? I read the user's guide but it wasn't much help. I would appreciate it if I can find an example of a startup.a51 modified for custom use. (I am new to Keil) Thanks

Read-Only Author erik malund Posted 16-Apr-2004 14:30 GMT Toolset C51	RE: Startup.a51 erik malund Is there some detailed explanation of startup.a51? WHY?. I used Keil for years and hardly knew it existed. Do you have a SPECIFIC reason for your inquiry? Erik

Read-Only Author Mohammad Adel Posted 16-Apr-2004 15:03 GMT Toolset C51	RE: Startup.a51 Mohammad Adel Does this mean that iit is not important to use startup.a51? If so, then in what cases should it be used? Or does it mean that it is not important to know its details? thanks

Read-Only Author Frank Hu Posted 16-Apr-2004 16:35 GMT Toolset C51	RE: Startup.a51 Frank Hu Hi Mohammad, I always include startup.a51 in my project. The reasons are: 1. I am using winbond 78E516, and it has an AUX-RAM on the chip. I have to modify the startup.a51 to init this memory area. 2. I want to have a full control of my source code. Even if I don't have to change the startup.a51, I'd prefer to have it included in my project, then I can step through the code before it jump to main. It's useful especially when you have a hardware problem (I mean bad mem W/R). As to the detail explaination, I think you can read the source code of startup.a51, It's kind of self-explained to me. Have a nice day! Frank

Read-Only Author Mohammad Adel Posted 16-Apr-2004 17:59 GMT Toolset C51	RE: Startup.a51 Mohammad Adel Thanks Frank.. The problem with the file is that i am not that good at assembly. I can understand the codes that clear memory, but other parts seem rather ambigous

Read-Only Author erik malund Posted 16-Apr-2004 17:05 GMT Toolset C51	RE: Startup.a51 erik malund 1)Does this mean that iit is not important to use startup.a51? 2)Or does it mean that it is not important to know its details? 1) it is not "important" it is REQUIRED if you have any C code. 2) I did not know the details for years, never looked. Erik

Read-Only Author Mohammad Adel Posted 16-Apr-2004 18:00 GMT Toolset C51	RE: Startup.a51 Mohammad Adel Thanks...

Read-Only Author Drew Davis Posted 17-Apr-2004 04:34 GMT Toolset C51	RE: Startup.a51 Drew Davis I can understand the codes that clear memory, but other parts seem rather ambigous As a public service, here are the parts of the standard Keil-supplied STARTUP.A51 that do not involve clearing memory. CSEG AT 0 ?C_STARTUP: LJMP STARTUP1 The 8051 always begins execution at address 0, which is also the beginning of the interrupt vector table. This code makes the startup vector jump to the startup code located at STARTUP1. (Much memory initialization deleted...) MOV SP,#?STACK-1 This code initializes the stack pointer to point at the stack segment defined to hold the stack. ; This code is required if you use L51_BANK.A51 with Banking Mode 4 ; EXTRN CODE (?B_SWITCH0) ; CALL ?B_SWITCH0 ; init bank mechanism to code bank 0 This code is required if you use L51_BANK with banking mode 4 to do bank switching. It initializes the bank switching mechanism to start off in bank 0. If you're not doing this, leave the call commented out. LJMP ?C_START This code jumps to the start of your C code -- that is, main(). END And that's it. Not much in there at all. You'll often want to modify STARTUP.A51 when you have an 8051 variant with nifty optional features like built-in memories or banking or peripherals that require some initialization of chip-specific registers.

Read-Only Author Mohammad Adel Posted 21-Apr-2004 01:16 GMT Toolset C51	RE: Startup.a51 Mohammad Adel Thanks...

Read-Only Author Andrew Neil Posted 21-Apr-2004 06:48 GMT Toolset C51	RE: Startup.a51 Andrew Neil LJMP ?C_START This code jumps to the start of your C code -- that is, main(). Not quite. C_START is the start of Keil's 'C' runtime startup: this includes, among other things, the code to setup all the values of initialised variables. Once this code has completed, it then jumps to main(). As someone else mentioned earlier, you can step through all this if you want...

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