CY8C Series 开机检测问题 How to detect touching activity when start the device (PSOC/PSOC4)

[TiMa_4677736]

We use CY8C4045 for touch detection and found a issue. When you touch the sensing area and then turn on the device, it will not detect until you move away and touch again. Please anyone help us with this issue.

One of the initial solutions is at the beginning of the device start, set the sensitivity extremely high to detect the slight difference while touching. Change the touching status positive and then after short amount of time change the sensitivity back to normal.

I would like to know since this is a very common issue if anyone have the mature solution for this?

我们使用CY8C4045进行触摸检测，发现了一个问题。 当触摸感应区域然后打开设备电源时，只有移开并再次触摸它才能检测到。 如果有解决方案请提供帮助。

我们初步的解决方案之一是在设备启动之初，将灵敏度设置为极高，以检测触摸时的细微差异。 将状态改为触摸状态，然后在短时间后将灵敏度恢复为正常。

我想知道，因为这是一个非常普遍的问题，是否有人有成熟的解决方案？

Really appreciate it!

非常感谢！！

Best regards，

Tina Ma

Electrical Engineer

[LinglingG_46]

1: 手指触摸在sensor上面，从CSD的触发原理方面分析，这是合理的。因为系统就是通过叠加手指电容，导致系统电容增量达到触发的阈值来判断sensor被trigger的。

2：如果把灵敏度调的太高的话，会导致误触发的。

3： 你能否描述一下，你是一个什么样的系统？ 为什么需要检测上电手指按在sensor上面的情况？

[TiMa_4677736]

It is a device that needs to recognize whether it is worn. It needs to be worn while it is off, turned on, and then the system recognizes that it is now in a wearing state. Is it possible to adjust the sensitivity just in a short time to sense that it has been worn and then change to normal sensitivity.

Or is there any other method.

是一个需要识别是否在佩戴状态的设备。需要做到关机时佩戴上，开机，然后系统识别现在是佩戴状态。是否可以调节灵敏度刚刚好在很短的时间感应已佩戴然后改变至正常灵敏度。

或者有没有其他方法。

[LinglingG_46 · Accepted solution]

建议通过读取sensor的寄生电容值来做区分。

没有手指按压的时候会对应一个sensor的电容，如果手指按在上面的话，电容值就会发生变化，通过这个逻辑来判断。

具体怎么操作，请查看datasheet 中built in self-test 章节。built in self-test(BIST)