How is the 16-bit timer setup?
Answer The 16-bit timer/counter is a count up counter, which upon reaching a value of 65535 (0FFFFH) will reset itself to 0000H and generate an internal interrupt signal. To obtain different timer counts, say N, of less than 65536, the timer should be first preset with a fixed value of 65536-N. After setting up this preset value the timer should be activated which will enable it to count from this preset value to 65535. The value that the timer is to count N, is therefore given by the formula 65536-(65536-N)=N.