How to delay the delay function

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How the delay function delays

** Function example                                                               Compiled by the compiled software   Assembly instruction 
Delay_ms（200）;                                         //     1、 0x0000058C 20C8      MOVS     r0,#0xC8
void Delay_ms(unsigned int time)
{
    unsigned char  n;
   while(time>0)                                               //       3、0x00000210 2800      CMP      r0,#0x00                                                                             
    {
			for(n=0;n<4;++n)                                  //      4、 0x00000204 2100      MOVS     r1,#0x00
			{                                               //   5、 0x00000206 1C49      ADDS     r1,r1,#1
				;                                           //  6、 0x00000208 B2C9      UXTB     r1,r1
				                                            // 7、 0x0000020A 2902      CMP      r1,#0x02
				                                           //    8、 0x0000020C D3FB      BCC      0x00000206
				                                           //    9、 0x0000020E 1E40      SUBS     r0,r0,#1
			}
			time--;                                    //     2、  0x00000202 E005      B        0x00000210
		}
}

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What you need to know 1、 Each assembly instruction takes several clock cycles , Easy to calculate how much time 2、 The clock period is 1M when , The reciprocal is time 1us

Text interpretation

Program entry Delay_ms（200） After delay function , The running sequence of the corresponding assembly instructions is 1——2——3——4——5——6——7——8——9 Among them for The assembly instructions for an empty loop are 5、6、7、8、9 These four , Get into for The number of times these four instructions are run in a loop is 4( From your own settings n<4） The corresponding assembly instructions in this function generally occupy one clock cycle , Among them the first 2 and 8 There are jump instructions , Occupy 2 Clock cycles , The hardware clock of this function program is set to 22MHz, Therefore, the delay function time is （10+8*（n-1））*（1/22M）us

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