How to do use led_pwm's LEDC_HSCH(0 or 1)_HPOINT_REG?

[Shaco.Ma]

Hi:
I had make a pwm high speed mode just output 100 cycle_cnt,in esp32_technical_reference_manual.pdf,picture 87. I want high timer ch0 use the 50% duty , and just have 100 hpoint,when the value of counter had reach hpoint , sig_out(?) will be high level, no pwm;for this , I set LEDC.channel_group[speed_mode].channel[channel_num].hpoint.hpoint, but no effect, What I do wrong?