Jellis

There seems to be some inconsistency in your code. Before the while, you write 7,i
In the while, you do i=i+c1 followed by write 8,i The variable i being a word sized entity would write to 8,9. Is this what you're seeing? Location 8 will always read 0 since the high byte of i would be zero (you're counting till 20 only). Other than this, the only reason for not breaking out of the code will be C1 never catches any counts.

Jerson