51 MCU interrupt number and timer working mode

Interrupt number                         interrupt 0 external interrupt 0 (EX0)                        interrupt 1 timer/timer interrupt 0 (ET0)                        interrupt 2 external interrupt 1 (EX1)                        interrupt 3 timer/timer interrupt 1 (ET1)                        interrupt 4 serial port interrupt (ES)                                          Timer working mode  1. Mode 0                     is composed of 8 bits of TH0 and the lower 5 bits of TL0 to form a 13-bit timer.                     When the 13-bit timer increases from 0 or the set value to all '1', an overflow occurs when it is increased by 1 again                     . At this time, set the TF0 bit of TCON to 1, and initialize the timer to all '0'   2. Mode 1                     Mode 1 and Mode 0 work the same way, the only difference is that TH0 and TL0 form a 16-bit counter.                     The reset method is the same as method 0.  3. Method 2             configures TL0 as an 8-bit timer that can automatically restore the initial value (initial constants are automatically reloaded)                      . TH0 is used as a constant buffer. TH0 is preset by software. When TL0 overflows, the                     overflow flag is set to 1, and the 8-bit data in TH0 is reloaded into TL0.                               Method 2 is often used for timing control. For example, if you want to generate a timing control pulse every 250us,                     you can use a 12MHz oscillator, preset TH0 to 6, and make C/=0 to achieve it. Method 2                    is not used as a serial port baud rate generator.   4. Method 3             Method 3 is different for timer T0 and timer T1 .             If T1 is set to method 3, it will stop working (the effect is the same as TR1=0),             so method 3 is only applicable to T0