Lpc2000

vaneenbergen wrote:

>That the first bit of the second byte also changed is very possible. 
>This is de to the processor. The timer register should be handled in 
>a 32 bit access. this is what i found out. so instead of these kind 
>of structures i just handle them in 32-bit. this way it is also 
>quicker, you can change all values at the same time.
>
>is this really the fault of the compiler?????
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He didn't understand what it was that he wrote so how can he answer that 
question?


TomW





>BTW using rowley and being very happy with it.
>
>Joost van Eenbergen
>ELC lighting
>
>--- In lpc2000@yahoogroups.com, Tom Walsh <tom@o...> wrote:
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>>Alex_Rambler wrote:
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>>>b> Just one data point, but: I'm a professional developer (30 
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>years s/w
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>>>b> development experience from micros to mainframes).  Now 
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>working on 
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>>>b> third LPC-based commercial product.  Compared Keil, IAR, and 
>>>      
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>gcc and 
>  
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>>>b> chose Rowley Crossworks (gcc-based).
>>>
>>>Oh, I can't hold out from the reply.
>>>I tried to use Crossworks in the begining to explore LPC2xxx.
>>>It ugly work with the structures. I tried to define T0MCR like
>>>struct:
>>>{{
>>>typedef struct
>>> { 
>>>   __REG32 MR0I :1;
>>>   __REG32 MR0R :1;
>>>   __REG32 MR0S :1;
>>>
>>>   __REG32 MR1I :1;
>>>   __REG32 MR1R :1;
>>>   __REG32 MR1S :1;
>>>   
>>>   __REG32 MR2I :1;
>>>   __REG32 MR2R :1;
>>>   __REG32 MR2S :1;
>>>   
>>>   __REG32 MR3I :1;
>>>   __REG32 MR3R :1;
>>>   __REG32 MR3S :1;    
>>>   __REG32      :4;    
>>>} __txmcr_bits;
>>>
>>>#define T0MCRbits (*(volatile __txmcr_bits *)0xE0004014)
>>>
>>>}}
>>>
>>>but when I handle to it, Crossworks GCC compile it to this code:
>>>
>>><<T0MCRbits.MR0I = 1;>>
>>>
>>>mov r3, #0xE0000000
>>>add r3, r3, #0x00004000
>>>add r3, r3, #0x00000014
>>>ldrb r2, [r3]
>>>orr r2, r2, #0x00000001
>>>strb r2, [r3]
>>>
>>>so, I get change in LSB and _in_the_second_byte_!.
>>>
>>> 
>>>
>>>      
>>>
>>Huh?  I only see the LSB getting changed, where do you see a 
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>second byte 
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>>involved??
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>>_ldrb_ and _strb_ are byte operations, not word ops.
>>
>>You got what you said in the typedef, assignment of address to the 
>>structure, and the the bit being set in T1MCR.  What is your 
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>problem???  
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>>As I read the code, nothing looks out of place, it all makes 
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>sense...
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>>TomW
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>>
>>-- 
>>Tom Walsh - WN3L - Embedded Systems Consultant
>>http://openhardware.net, http://cyberiansoftware.com
>>"Windows? No thanks, I have work to do..."
>>----------------------------------------------------
>>
>>    
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>Yahoo! Groups Links
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-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
"Windows? No thanks, I have work to do..."
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