Hey all, I am using uVision 3 and a Phytec 2294 board. I have an external memory device connected to the phytec expansion board. The external device is using /CS0, although from talking to phytec, I am not sure if that is quite right. I have set up the external memory space in the project options like so: Start: 0x80000000 Size: 0x4 When I define a variable like :
#define volatile var x __at 0x8000000
Much better. Thank you.
0x00000606 E7F1 B 0x000005EC 27: int main (void) { 28: unsigned int j; /* LED var */ 29: 0x00000608 B500 PUSH {LR} ;Just saving some processor context there.
30: MY_REG1 = 1; 31: 0x0000060A 2101 MOV R1,#0x01 ;Loading R1 with the value to be written. 0x0000060C 4813 LDR R0,[PC,#0x004C] ;Loading R0 with the address to write to. 0x0000060E 7001 STRB R1,[R0,#0x00] ;Performing the byte write.
Dan, Another thing I just noticed is that if I stored this in the target options start of 0x83000000, and size of 0x4, the compiler gives me this:
*** ERROR L107: ADDRESS SPACE OVERFLOW SPACE: DATA SEGMENT: STACK LENGTH: 00000490H *** WARNING L23: UNRESOLVED EXTERNAL SYMBOLS *** ERROR L128: REFERENCE MADE TO UNRESOLVED EXTERNAL SYMBOL: ?C?INIT ADDRESS: 00000104H Program Size: data=1172 const=0 code=296 Target not created
"Any idea why it doesnt like the smaller size?" The only thing I can think of is that the mapper is designed to deal with larger chunks, for example >=256-bytes. My Linux kernel rounds everything up to 4KiB pages ;-)
Dan, Thanks again for your help today. I think this is enought to go on for now. If I need to specify a bigger chunk, its not too much of a big deal :) Im going to use it or im not, end of that. Again, thanks for the assistance. This beginning embedded guy really appreciates it :)
You bet. Have fun!