There are some questions about the cable detection.
The following are the phenomena encountered during use.
1. The current design is to turn on the enable every 5 seconds. After the enable is turned on for 1ms, read the counting register of LMH0303 to judge whether there is a device connected. Turn on when the counter is less than 25, otherwise turn off.
During the test, it was found that the LMH0303 was turned on abnormally when it was not connected to the device, and the value of the counting register was in an unstable state, distributed from 0 to 31.
In the same environment, adjust the enable opening time from 1mm to 5mm, and read the value of the counting register at 5ms to judge whether the device is connected. At this time, there is no abnormal opening, and the value of the counting register is stable at 30~31. Fewer times 28,29.
2. The customer read the value of the counting register after the enable is turned off for a period of time. At this time, the value is distributed from 16 to 31 (the read value will not change with time after the enable is turned off).
Here is the questions:
Q1. After LMH0303 is enabled, read the counting register within 1ms (datasheet is 4ms). At this time, whether the value of the counter is an abnormal value has no reference meaning and cannot be used for insertion detection. The datasheet needs 4ms. Is it necessary to read the value of the count register 4ms after enabling? Why is there such a requirement of 4ms?
Q2.After the enable is completely closed, is it meaningful to read the value of the counter? It is normal to read the value when the enable is turned on. What is the reason?