请问各位大佬，我想用ESP32来改变某几个引脚电平，时序要求严格，需要满足微秒级延时，且脉冲宽度也为微秒级。
我现在是用的while(i){i--};通过改变i的值来实现想要的延时。但用示波器测出来的脉冲宽度不稳定，但都是差了4微秒的整数倍。
我查了一些资料，但是都没有解决。感觉是优先级的问题，被别东西打断了。
我用了portENTER_CRITICAL(mux);进入临界区，但是并没有改善。（不过，第二个参数我不大理解该怎么设置）

请问大家有知道原因的吗？
本人小白，新接触这个领域，向各位学习！

附上一段延时代码，恳请大家批评指正！

portMUX_TYPE a;
a.owner = CORE_ID_APP;
a.count = 2;

        for (int i = 0; i < n; i++)
        {
            portENTER_CRITICAL(&a);
            switch (ioio[i])
            {
            case 0://0
                GPIO.out_w1tc = 0x02000000; GPIO.out_w1tc = 0x04000000; GPIO.out1_w1tc.data =0x00000001; GPIO.out1_w1tc.data =0x00000002; break;
            case 1://1
                GPIO.out_w1tc = 0x02000000; GPIO.out_w1tc = 0x04000000; GPIO.out1_w1tc.data =0x00000001; GPIO.out1_w1ts.data =0x00000002; break;
            case 2://2
                GPIO.out_w1tc = 0x02000000; GPIO.out_w1tc = 0x04000000; GPIO.out1_w1ts.data =0x00000001; GPIO.out1_w1tc.data =0x00000002; break;
            case 3://3
                GPIO.out_w1tc = 0x02000000; GPIO.out_w1tc = 0x04000000; GPIO.out1_w1ts.data =0x00000001; GPIO.out1_w1ts.data =0x00000002; break;
            case 4://4
                GPIO.out_w1tc = 0x02000000; GPIO.out_w1ts = 0x04000000; GPIO.out1_w1tc.data =0x00000001; GPIO.out1_w1tc.data =0x00000002; break;
            case 5://5
                GPIO.out_w1tc = 0x02000000; GPIO.out_w1ts = 0x04000000; GPIO.out1_w1tc.data =0x00000001; GPIO.out1_w1ts.data =0x00000002; break;
            case 6://6
                GPIO.out_w1tc = 0x02000000; GPIO.out_w1ts = 0x04000000; GPIO.out1_w1ts.data =0x00000001; GPIO.out1_w1tc.data =0x00000002; break;
            case 7://7
                GPIO.out_w1tc = 0x02000000; GPIO.out_w1ts = 0x04000000; GPIO.out1_w1ts.data =0x00000001; GPIO.out1_w1ts.data =0x00000002; break;
            case 8://8
                GPIO.out_w1ts = 0x02000000; GPIO.out_w1tc = 0x04000000; GPIO.out1_w1tc.data =0x00000001; GPIO.out1_w1tc.data =0x00000002; break;
            case 9://9
                GPIO.out_w1ts = 0x02000000; GPIO.out_w1tc = 0x04000000; GPIO.out1_w1tc.data =0x00000001; GPIO.out1_w1ts.data =0x00000002; break;
            case 10://10
                GPIO.out_w1ts = 0x02000000; GPIO.out_w1tc = 0x04000000; GPIO.out1_w1ts.data =0x00000001; GPIO.out1_w1tc.data =0x00000002; break;
            case 11://11
                GPIO.out_w1ts = 0x02000000; GPIO.out_w1tc = 0x04000000; GPIO.out1_w1ts.data =0x00000001; GPIO.out1_w1ts.data =0x00000002; break;
            case 12://12
                GPIO.out_w1ts = 0x02000000; GPIO.out_w1ts = 0x04000000; GPIO.out1_w1tc.data =0x00000001; GPIO.out1_w1tc.data =0x00000002; break;
            case 13://13
                GPIO.out_w1ts = 0x02000000; GPIO.out_w1ts = 0x04000000; GPIO.out1_w1tc.data =0x00000001; GPIO.out1_w1ts.data =0x00000002; break;
            case 14://14
                GPIO.out_w1ts = 0x02000000; GPIO.out_w1ts = 0x04000000; GPIO.out1_w1ts.data =0x00000001; GPIO.out1_w1tc.data =0x00000002; break;
            case 15://15
                GPIO.out_w1ts = 0x02000000; GPIO.out_w1ts = 0x04000000; GPIO.out1_w1ts.data =0x00000001; GPIO.out1_w1ts.data =0x00000002; break;
            default: ESP_LOGI(TAG,"error"); break;
            }
            portEXIT_CRITICAL(&a);
            while(delay[i]){delay[i]--;}
        }

//main中的任务语句
xTaskCreatePinnedToCore(&new_send_pulse, "new_send_pulse", 4096, NULL, 0, NULL, 1 );