Lpc2000

Alex_Rambler wrote:

>b> Just one data point, but: I'm a professional developer (30 years s/w
>b> development experience from micros to mainframes).  Now working on 
>b> third LPC-based commercial product.  Compared Keil, IAR, and gcc and 
>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 second byte 
involved??

_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 problem???  
As I read the code, nothing looks out of place, it all makes sense...


TomW



-- 
Tom Walsh - WN3L - Embedded Systems Consultant
http://openhardware.net, http://cyberiansoftware.com
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