请教Microchip的TCP/IP stack 中定时器初值的计算公式
#define CLOCK_FREQ (41666667) // Hz
#define INSTR_FREQ (CLOCK_FREQ/4)
#define TICKS_PER_SECOND (100) // 10ms
#define TICK_LOAD ((WORD)((-(INSTR_FREQ+2+TICKS_PER_SECOND/2)/4/TICKS_PER_SECOND)+4))
TICK_LOAD计算出来的值为 0x9A4B,我自己算出来的值和这个值相差4.想请教下上面((WORD)((-(INSTR_FREQ+2+TICKS_PER_SECOND/2)/4/TICKS_PER_SECOND)+4))是怎么来的?