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Hello iam working on cygnal microcontrollers c8051f124,iam performing checksum as i written below. The datas are written in external memoryarea when iam performing checksum at 4th byte operation iam exeeding the 8 bit register value ie sum=7b+ff=17a(378 inn decimal) but microcontroller is holding only 0x007a its ignoring overflow 1.but i defined sum as unsigned short int its not holding the overflow of ff value what i have to do now? johne char xdata test_string[100]_at_ 0x5555={0x0f,0x2e,0x3e,0xff,0xff,0x00,0xfe,0xff}; void main() { int x=8,y; unsigned short int sum=0; for(y=0;y<8;++y) { sum=sum+test_string[y]; if(sum>0xff) { sum=sum-0xff; } } test_string[y]=0xff-sum; test_string1[100]=test_string[100]; printf("checksum=%x\n",test_string[y]); }
"microcontroller is holding only 0x007a its ignoring overflow" How do you know this? Are you relying on your printf output?
printf("checksum=%x\n",test_string[y]);
test_string1[100]=test_string[100];
Hello mr neil thanks for your reply john e