[U-Boot] Strange data behaviour

Remco Poelstra remco.poelstra at duran-audio.com
Tue Feb 17 12:55:36 CET 2009


Hi,

I'm trying to get my LPC2468 based board to work. I've some problems 
with the external memory databus.
I would like to know the settings of internal registers to see whether 
I've initialized them correctly, so I tried making a function that 
prints the content over the serial link. I'm still in the lowlevel_init 
function, so I do not have the U-boot puts functions available.
I wrote the following function to convert a long to a HEX string:
-------------------
void print_long(unsigned long data) {
   char i;
   char 
hex_data[]={'0','1','2','3','4','5','6','7','8','9','A','B','C','D','E','F'};

   for(i=0; i<8; i++) {
     while((U0LSR & (1<<5)) == 0); /* Wait for empty U0THR */
//    U0THR = hex_data[(0xDEADBEEF>>i*4)&0xF];
     U0THR = hex_data[(0xDEADBEEF>>4)&0xF];
   }
}
---------------
When I run it likes this I get 8 E's. Which is what I expect. When I run 
it with the commented-out line, I get back 8 0x0's. So it seems that the 
output is only correct when it is constant.
Does anyone have a clue on why that is?

Kind regards,

Remco Poelstra



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