A disc type pulley touch detection method applied to an FPC flexible circuit board

Abstract

The application belongs to the technical field of touch key detection, and particularly relates to a disc type pulley touch detection method applied to an FPC flexible circuit board. The method comprises the following steps: obtaining a touch maximum value, a touch intermediate value and a touch minimum value of each key through register initialization and double-frequency hopping touch scanning; taking the difference between the touch maximum value and the touch minimum value as a noise value of each key; comparing the noise value according to a preset noise judgment condition to judge whether the touch detection system is currently in a noise environment, and setting or clearing a noise flag bit accordingly; selecting the touch intermediate value or the touch minimum value as a current effective touch value according to the noise flag bit; and slowly updating touch reference values of the keys in a weighted manner under the condition that there is no effective touch and touch change is stable. The application solves the problems of unstable key pressing and sensitivity deviation of a touch pulley system.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of touch key detection, and particularly relates to a disc type pulley touch detection method applied to an FPC flexible circuit board. BACKGROUND

[0002] In recent years, capacitive touch key detection technology has rapidly developed worldwide, and touch keys are gradually replacing traditional mechanical keys and becoming a new choice in various key application fields. Compared with mechanical keys, capacitive touch keys only need to be lightly touched by a finger to achieve sensitive and rapid control response, and have the advantages of no physical wear and tear, strong sealing, and more widely adapted scenarios.

[0003] With the continuous expansion and deepening of touch interaction, in core application fields such as home appliances and vehicles, the basic touch key solution has been difficult to meet market demand, and the market demand for pulley touch and slide touch touch interaction solutions that can achieve fine control has sharply increased.

[0004] Existing touch detection solutions mostly use one key to achieve one gear adjustment, or use a key pad: a spring, conductive foam or other medium is used to connect the PCB and the panel, one PAD corresponds to one key, and the keys are cascaded to form a pulley or slide effect.

[0005] However, the existing technology mainly has the following technical defects:

[0006] 1) The current touch implementation method is implemented on a hard PCB circuit board, which has high limitations and poor flexibility, and is not suitable for touch products with small space and structure;

[0007] 2) The touch panel of the product cannot cover components, otherwise it will affect the touch panel adhesion and touch sensitivity. Display devices and ICs need to be arranged on the front and back, increasing the smt cost;

[0008] 3) The method of connecting the control board and the main control board mostly needs to insert the terminal, and the structure installation is limited;

[0009] 4) The use of multiple keys to cascade to achieve a pulley effect has poor sliding effect and the keys are easy to lose, and the finger between two keys will cause the keys to vibrate, and the keys will also jump during the related reliability experiment. SUMMARY

[0010] The purpose of the application is to provide a disc type pulley touch detection method applied to an FPC flexible circuit board, which adopts a double-frequency four-threshold detection method under the condition of meeting sensitivity, solves the problem of unstable point pressing of the pulley system during sliding, and is easy to pass the related reliability experiment.

[0011] To solve the above technical problems, the application provides a disc type pulley touch detection method applied to a FPC flexible circuit board, which comprises the following steps:

[0012] By initializing the register and double-frequency hopping touch scanning, multiple sampling and filtering processing are performed to obtain a touch maximum value, a touch intermediate value and a touch minimum value of each key;

[0013] The difference between the touch maximum value and the touch minimum value is taken as a noise value of each key; the noise value is compared according to a preset noise judgment condition to judge whether the touch detection system is currently in a noise environment, and a noise flag bit is set or cleared accordingly;

[0014] According to the noise flag bit, the touch intermediate value or the touch minimum value is selected as a current effective touch value; under the condition that there is no effective touch and the touch change is stable, the touch reference values of the keys are slowly updated in a weighted manner;

[0015] According to the noise flag bit, a preset threshold value of each key is dynamically adjusted to form four kinds of judgment threshold values, including a touch sliding maximum effective value, a single key threshold value, a combination key threshold value and a touch sliding minimum value;

[0016] By calculating the difference between the touch intermediate value of each key and the corresponding reference value and introducing a preset redundancy interval, the key with the maximum difference value is determined as a reference point for touch position judgment;

[0017] By executing a preset state judgment logic based on the reference point, the historical gear state recorded by the touch detection system, the difference values of the keys and the four kinds of judgment threshold values, the current touch gear is determined and output;

[0018] The state judgment logic comprises:

[0019] When the historical gear state is a combination key gear related to the reference point, a first judgment sub-process is executed; the first judgment sub-process comprises: judging whether the difference value of another key constituting the combination key gear is greater than the corresponding touch sliding minimum value; if yes, it is judged that the combination key gear is maintained; if no, a second judgment sub-process is executed;

[0020] When the historical gear state is a single key gear related to the reference point, the second judgment sub-process is executed; the second judgment sub-process comprises: judging whether the difference value of the reference point is greater than a single key judgment threshold value, if yes, it is judged that the single key gear corresponding to the historical gear state is maintained; if no, it is judged as a no-touch gear; wherein the single key judgment threshold value is the single key threshold value corresponding to the reference point minus a preset redundancy; the preset redundancy is half of a preset noise threshold value;

[0021] When the historical gear state is a no-touch gear, a third determination sub-process is executed; the third determination sub-process includes: determining whether the difference of the adjacent key related to the reference point is greater than the corresponding combined key threshold value; if yes, determining that the reference point and the adjacent key constitute a combined key gear; if no, determining whether the difference of the adjacent key is greater than the touch sliding minimum value and the sum of the difference of the reference point and the difference of the adjacent key is greater than the sum of the combined key threshold values of the two; if yes, determining the corresponding combined key gear; determining whether the difference of the reference point is greater than the single key threshold value; if yes, determining the single key gear corresponding to the reference point; if none of the above conditions is met, determining the no-touch gear.

[0022] Preferably, the dual-frequency hopping touch scanning is performed multiple times and filtering processing is performed, including: scanning four touch keys of the disc layout using two different touch detection frequencies, obtaining touch values of each key at two different frequencies, and sampling three times, respectively marked as maximum value, minimum value and intermediate value three data, and performing average and first-order filtering processing on the three data and the corresponding values of the last time to obtain the touch maximum value, touch intermediate value and touch minimum value of each key; wherein the touch detection frequencies are normal distribution and uniform distribution respectively.

[0023] Preferably, the preset noise determination condition includes:

[0024] The noise flag position start state includes: in the continuous two times of scanning, the number of keys whose noise values are greater than the preset noise threshold value exceeds one half of the total number of keys, or in the continuous two times of scanning, the noise value of the same key is greater than the preset noise threshold value, then it is considered that the touch detection system is in a noise environment, and the noise flag position is started;

[0025] The noise flag bit clear state includes: under the condition of no key, the noise values of all keys are less than the preset noise threshold value for 100 times continuously, or under the condition of having keys, the noise values of all keys are less than the preset noise threshold value for 300 times continuously, then it is considered that the touch detection system is in a noise-free environment, and the noise flag bit is cleared.

[0026] Preferably, if the touch detection system is in a noise environment, the current effective touch value adopts the minimum value; if the touch detection system is not in a noise environment, the current effective touch value adopts the intermediate value;

[0027] The updating of the touch reference value of each key needs to meet the following conditions:

[0028] Condition 1: the touch jitter value is less than the preset noise threshold value; the touch jitter value is the difference between the current effective touch value and the last effective touch value;

[0029] Condition 2: no key is pressed at present and no key is pressed in the trend, i.e. the touch jitter value is less than the preset touch minimum change amount;

[0030] After the above two conditions are met, the touch reference value is refreshed after a delay of 1s, and the touch reference value is updated according to the weighted formula of "new touch reference value = original touch reference value × 3 / 4 + current effective touch value × 1 / 4".

[0031] Preferably, the preset threshold value of each key is dynamically adjusted to form four kinds of determination thresholds, including:

[0032] When the noise flag indicates a non-noise environment, 120%, 70%, 30% and 20% of the preset threshold value are taken as the touch sliding maximum effective value, the single key threshold value, the combination key threshold value and the touch sliding minimum value, respectively;

[0033] When the noise flag indicates a noise environment, 130%, 80%, 40% and 30% of the preset threshold value are taken as the touch sliding maximum effective value, the single key threshold value, the combination key threshold value and the touch sliding minimum value, respectively.

[0034] Preferably, it further comprises an abnormal protection step: if the difference of any key is greater than the touch sliding maximum effective value and lasts for a certain length of time, the system protection is triggered, and all touch outputs are reset.

[0035] Preferably, the touch gear includes four single key gears corresponding to four independent touch keys, four combination key gears corresponding to four adjacent touch keys triggered at the same time, and one no-touch gear, totaling nine key states.

[0036] Preferably, before executing the state determination logic, it further comprises an effectiveness verification step: calculating the difference between the touch maximum value and the touch minimum value of all keys in the current scanning period, if the difference is less than twice the preset noise threshold, the touch is determined to be valid, and the state determination logic is executed; otherwise, this determination is abandoned.

[0037] The application also provides a disc type pulley touch detection system applied to an FPC flexible circuit board, comprising:

[0038] The touch sensing pulley is composed of four touch keys in a disc type layout, and is used for realizing touch input of a special-shaped structure product through a flexible circuit board.

[0039] The processing control module is configured to execute the disc type pulley touch detection method applied to the FPC flexible circuit board.

[0040] Compared with the prior art, the application has the following beneficial effects:

[0041] The application can be used for special-shaped touch structure products, has small appearance limitation, and can realize touch eight-grade adjustment by using only four keys, supports sliding touch and point touch, and is stable without shaking. 2mm space touch is supported, components can be arranged on a single panel, the panel directly covers above the components, and the smt cost of the flexible circuit board is reduced. Under the condition of meeting the sensitivity, a double-frequency four-threshold detection method is used, combined with historical gear state guidance, the recognition shaking problem generated at the key junction in the sliding process is effectively solved, smooth transition and stable locking between points are realized, point pressing operation is accurate, the problem of unstable point pressing of the sliding wheel system in sliding is solved, and the requirements of EMI / CS authentication are more easily met. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 It is a touch detection method flow chart of a touch key provided by the application.

[0043] Figure 2 It is a method flow chart of touch sliding wheel sliding positioning and single key positioning provided by the application. DETAILED DESCRIPTION

[0044] The application will be further described in detail below in combination with the drawings and specific embodiments. According to the following description, the advantages and characteristics of the application will be more apparent. It should be noted that the drawings are all very simplified and use non-precise proportions, and are only used to facilitate and clearly assist the purpose of describing the embodiments of the application.

[0045] As shown in Figure 1 and Figure 2 , the embodiment of the application provides a disc type sliding wheel touch detection method applied to an FPC flexible circuit board, and specifically includes the following steps:

[0046] Step 301: initialize and set the register used by the touch key module, and provide a basic state.

[0047] Step 302: respectively use two different touch detection frequencies to perform touch scanning, the touch detection frequencies are normal distribution and uniform distribution, this frequency hopping method can effectively reduce the influence of strong interference of fixed frequency on original touch data, and can also reduce the radiation disturbance generated to the outside.

[0048] Step 303: take the touch value of a touch key at different frequencies, sample three times, and mark the maximum value, the minimum value and the intermediate value respectively.

[0049] Step 304: respectively average the touch maximum value, the intermediate value and the minimum value obtained by the two different touch detection frequencies with the last value, perform first-order filtering, obtain new intermediate value and minimum value for subsequent key state judgment.

[0050] Step 305: Noise judgment. By calculating the maximum and minimum values of the two frequency points respectively, the difference is recorded as the noise value. Compare the noise value with the noise value obtained in advance according to the touch debugging software.

[0051] The set noise value noise judgment condition is as follows:

[0052] ① The number of keys whose noise value is greater than the preset noise value exceeds 1 / 2 of the total number of keys for two consecutive times, and the system is considered to be in a noise environment, and the noise flag bit is set to 1.

[0053] ② The noise value of the same key is greater than the preset noise value for two consecutive times, and the system is also considered to be in a noise environment, and the noise flag bit is set to 1.

[0054] ③ Under the condition of no key, if the noise value of all keys is less than the preset noise value for 100 consecutive times, the system is considered to be in a noise-free environment, and the noise flag bit is cleared to 0.

[0055] ④ Under the condition of having keys, if the noise value of all keys is less than the preset noise value for 300 consecutive times, the system is also considered to be in a noise-free environment, and the noise flag bit is cleared to 0.

[0056] Step 306: Reference value update. If the system is not in a noise environment, the touch value adopts the intermediate value, and if the system is in a noise environment, the touch value adopts the minimum value. Get the difference between the current touch value and the last touch value, recorded as the touch jitter value. The reference value update needs to meet the following two conditions: 1) the touch jitter value is less than the preset noise value; 2) there is no key pressed and there is no trend of key pressed (the touch jitter value is less than the preset touch minimum change amount).

[0057] After meeting the above two conditions, refresh the reference value after 1s to ensure that the touch scroll effect is stable under the condition of doing reliability experiment. The new reference value is 3 / 4 of the original reference value + 1 / 4 of the existing touch value, which allows the reference value to update slowly and maintain the stability of the entire touch system.

[0058] Step 307: Four threshold value calculation. According to the touch debugging software, the threshold value of each key is obtained, and according to whether the system is in a noise environment, it is divided into the following two cases: 1) the system is in a non-noise environment: take 120%, 70%, 30% and 20% of the threshold value as the touch sliding maximum effective value, the single key threshold value, the combination key threshold value and the touch sliding minimum value respectively. 2) The system is in a noise environment: take 130%, 80%, 40% and 30% of the threshold value as the touch sliding maximum effective value, the single key threshold value, the combination key threshold value and the touch sliding minimum value respectively.

[0059] Step 308: Key number determination. First, determine whether it is a single key press, a combination key press, or a trend of three or more key presses. If it is a single key press or a combination key press, jump to step 309; if it is a trend of three or more key presses or no key press, jump to step 302.

[0060] Step 309: Key locking and preliminary determination. Scan all keys, respectively subtract the touch intermediate value of the two frequency points from the corresponding base value to obtain the difference value. Subtract 1 / 2 of the preset noise value from the obtained difference value, denoted as differData_comp[cnt], to create a touch position determination redundancy interval, which can avoid the situation of jitter at the junction of combination keys, obtain the key with the maximum touch difference value, and mark it as diffMaxPoint. The maximum touch difference value is denoted as diffDataMax. At the same time, calculate the difference between the maximum touch value and the minimum touch value, denoted as tk_differ. If tk_differ is less than 2 times the preset noise value, it is determined that this touch is valid, and jump to step 310. If tk_differ is greater than or equal to 2 times the preset noise value, jump to step 302.

[0061] Step 310: Position calculation. The four keys forming the pulley are respectively marked as TK1, TK2, TK3, and TK4, and the eight positions of the pulley are respectively TK1, TK1+TK2, TK2, TK2+TK3, TK3, TK3+TK4, TK4, and TK4+TK1. TK1 corresponds to position 1, TK1+TK2 corresponds to position 2, TK2 corresponds to position 3, TK2+TK3 corresponds to position 4, TK3 corresponds to position 5, TK3+TK4 corresponds to position 6, TK4 corresponds to position 7, and TK4+TK1 corresponds to position 8. No key corresponds to position 0. In step 309, the key point with the maximum difference value has been determined. If diffMaxPoint is TK1, the last position state related to TK1 can only be 0 (no key), 1 (TK1), 2 (TK1+TK2), and 8 (TK4+TK1). First, determine whether the current position is 8. If it is 8, jump to step 311; otherwise, jump to step 313.

[0062] Step 311: Calculate whether the difference value differData_comp[4] of TK4 is greater than the touch sliding minimum value. If it is greater than the touch sliding minimum value, position 8 is obtained; otherwise, jump to step 312.

[0063] Step 312: Obtain position 0.

[0064] Step 313: Determine whether the current position is 2. If it is 2, jump to step 314; otherwise, jump to step 315.

[0065] Step 314: Determine whether TK2 difference differData_comp[2] is greater than touch slide minimum. If greater than touch slide minimum, then position 2 is obtained, otherwise jump to step 312.

[0066] Step 315: Determine whether current position is 1. If 1, then jump to step 316, otherwise jump to step 317.

[0067] Step 316: Determine whether TK1 difference differData_comp[1] is greater than (TK1 single key threshold - 1 / 2 preset noise value). If greater than (TK1 single key threshold - 1 / 2 preset noise value), then position 1 is obtained, otherwise jump to step 312.

[0068] Step 317: Determine whether current position is 0. If 0, then no key is pressed or previous key is released. Only when current position is 0, the next key press can be detected, so that the key slide will not appear jitter in single key or combination key, and the reliability of the wheel detection system is enhanced. If current position is 0, jump to step 318, otherwise jump to step 319.

[0069] Step 318: Determine whether TK1 difference differData_comp[1] is less than (TK1 single key threshold - 1 / 2 preset noise value). The purpose is to determine whether TK1 key has a release trend. If less than (TK1 single key threshold - 1 / 2 preset noise value), then jump to step 320, otherwise jump to step 319.

[0070] Step 319: Exit this position determination, and jump to step 325.

[0071] Step 320: Determine whether TK4 difference differData_comp[4] is greater than TK4 combination key threshold. If greater than TK4 combination key threshold, then position 8 is obtained, otherwise jump to step 321.

[0072] Step 321: Determine whether TK4 difference differData_comp[4] is greater than TK4 touch slide minimum threshold, and whether TK4 difference and (differData_comp[4] + differData_comp[1]) are greater than the sum of TK4 combination key threshold and TK1 combination key threshold. If both conditions are met, then position 8 is obtained, otherwise jump to step 322.

[0073] Step 322: Determine whether TK2 difference differData_comp[2] is greater than TK2 combination key threshold. If greater than TK2 combination key threshold, then position 2 is obtained, otherwise jump to step 323.

[0074] Step 323: judge whether TK2 difference differData_comp[2] is greater than TK2 touch slide minimum threshold value, and TK1 difference and TK2 difference and (differData_comp[1]+ differData_comp[2]) is greater than the sum of TK1 combination key threshold value and TK2 combination key threshold value. If the above two conditions are met, position 2 is obtained, otherwise jump to step 324.

[0075] Step 324: judge whether TK1 difference differData_comp[1] is greater than TK1 single key threshold value, if greater than TK1 single key threshold value, position 1 is obtained, otherwise jump to step 319.

[0076] Step 325: judge whether all key difference differData_comp[cnt] is greater than touch slide maximum effective value, if there is a key greater than touch slide maximum effective value for 1 minute, trigger protection mechanism, clear 0 all touch output, jump to step 302.

[0077] In summary, the improved four threshold filtering algorithm and the method for determining touch key pressing of the application can perfectly solve the problem of unstable touch wheel system point pressing and sensitivity deviation, and can also pass the relevant reliability experiment in the strong magnetic interference scene.

[0078] The above description is only a description of the preferred embodiment of the application, and does not limit the scope of the application. Any modification or modification made by a person skilled in the art according to the above disclosure is within the protection scope of the claims.

Claims

1. A disc-type pulley touch detection method applied to FPC flexible circuit boards, characterized in that, include: By initializing the registers and performing dual-frequency hopping touch scanning, and by performing multiple sampling and filtering processes, the maximum touch value, the intermediate touch value, and the minimum touch value of each button are obtained. The difference between the maximum and minimum touch values ​​is used as the noise value for each button. Based on preset noise judgment conditions, the noise values ​​are compared to determine whether the touch detection system is currently in a noisy environment, and the noise flag is set or cleared accordingly. Based on the noise flag, the intermediate or minimum touch value is selected as the current valid touch value; Under the condition that there is no effective touch and the touch changes are stable, the touch reference value of each button is slowly updated in a weighted manner; Based on the noise flag bit, the preset threshold for each button is dynamically adjusted to form four judgment thresholds, including the maximum effective value of touch sliding, single key threshold, combination key threshold and minimum touch sliding value. By calculating the difference between the touch midpoint value of each button and the corresponding baseline value, and introducing a preset redundancy range, the button with the largest difference is determined as the reference point for touch position determination. Based on the reference point, the historical touch level recorded by the touch detection system, the difference between each button, and four judgment thresholds, a preset state judgment logic is executed to determine and output the current touch level. The state determination logic includes: When the historical gear position is a combination key gear position related to the reference point, the first determination sub-process is executed; the first determination sub-process includes: determining whether the difference between the other key constituting the combination key gear position and its corresponding minimum touch sliding value is greater than the minimum value; if yes, the combination key gear position is maintained; if no, the second determination sub-process is executed. When the historical gear position is a single-key gear position related to the reference point, a second determination sub-process is executed; the second determination sub-process includes: determining whether the difference of the reference point is greater than a single-key determination threshold; if yes, determining to maintain the single-key gear position corresponding to the historical gear position; if no, determining to be a no-touch gear position; wherein the single-key determination threshold is the single-key threshold corresponding to the reference point minus a preset redundancy amount; the preset redundancy amount is half of a preset noise threshold; When the historical gear state is a no-touch gear, a third determination sub-process is executed; the third determination sub-process includes: determining whether the difference between adjacent keys related to the reference point is greater than its corresponding combination key threshold; if yes, it is determined to be a combination key gear formed by the reference point and the adjacent key; if no, it is determined whether the difference between the adjacent keys is greater than its minimum touch sliding value, and whether the sum of the difference between the reference point and the difference between the adjacent keys is greater than the sum of their combination key thresholds; if yes, it is determined to be the corresponding combination key gear; determining whether the difference between the reference point is greater than its single key threshold; if yes, it is determined to be the single key gear corresponding to the reference point; if none of the above conditions are met, it is determined to be a no-touch gear.

2. The disc-type pulley touch detection method for FPC flexible circuit boards as described in claim 1, characterized in that, The dual-frequency hopping touch scanning, and the multiple sampling and filtering processes, include: scanning the four touch buttons in a circular layout using two different touch detection frequencies, obtaining the touch value of each button at the two different frequency points, and sampling it three times, marking it as the maximum value, minimum value and median value respectively. The three data are then averaged and first-order filtered with the corresponding value from the previous sampling to obtain the maximum touch value, median touch value and minimum touch value of each button; wherein the touch detection frequencies are normally distributed and uniformly distributed, respectively.

3. The disc-type pulley touch detection method for FPC flexible circuit boards as described in claim 1, characterized in that, The preset noise determination conditions include: The noise flag position is activated when: in two consecutive scans, the number of buttons with noise values ​​greater than a preset noise threshold exceeds half of the total number of buttons, or in two consecutive scans, the noise value of the same button is greater than a preset noise threshold. In this case, the touch detection system is considered to be in a noisy environment and the noise flag position is activated. The noise flag is cleared when: if the noise value of all buttons is less than the preset noise threshold for 100 consecutive times without any buttons, or if the noise value of all buttons is less than the preset noise threshold for 300 consecutive times with buttons, the touch detection system is considered to be in a noise-free environment and the noise flag is cleared.

4. The disc-type pulley touch detection method for FPC flexible circuit boards as described in claim 1, characterized in that, If the touch detection system is in a noisy environment, the minimum value is used for the current valid touch value; if the touch detection system is not in a noisy environment, the intermediate value is used for the current valid touch value. The update of the touch reference value for each button must simultaneously meet the following conditions: Condition 1: The touch jitter value is less than a preset noise threshold; the touch jitter value is the difference between the current valid touch value and the previous valid touch value; Condition 2: There is currently no button pressed and no trend of button pressing, that is, the touch jitter value is less than the preset minimum touch change amount; After the above two conditions are met, the touch reference value is refreshed after a 1-second delay, and the touch reference value is updated according to the weighted formula "new touch reference value = original touch reference value × 3 / 4 + current effective touch value × 1 / 4".

5. The disc-type pulley touch detection method for FPC flexible circuit boards as described in claim 1, characterized in that, The preset threshold for each button is dynamically adjusted to form four judgment thresholds, including: When the noise flag indicates a non-noise environment, 120%, 70%, 30%, and 20% of the preset thresholds are taken as the maximum effective value of touch sliding, the single key threshold, the combination key threshold, and the minimum touch sliding value, respectively. When the noise flag indicates a noisy environment, 130%, 80%, 40%, and 30% of the preset thresholds are taken as the maximum effective value of touch sliding, the single key threshold, the combination key threshold, and the minimum touch sliding value, respectively.

6. The disc-type pulley touch detection method for FPC flexible circuit boards as described in claim 1, characterized in that, It also includes an anomaly protection step: if the difference between any key and the maximum effective value of the touch swipe is greater than the maximum effective value and lasts for a certain period of time, the system protection is triggered, and all touch outputs are reset.

7. The disc-type pulley touch detection method for FPC flexible circuit boards as described in claim 1, characterized in that, The touch settings include: four single-key settings corresponding to four independent touch buttons, four combination key settings corresponding to four adjacent touch buttons being triggered simultaneously, and one no-touch setting, for a total of nine button states.

8. The disc-type pulley touch detection method for FPC flexible circuit boards as described in claim 1, characterized in that, Before executing the state determination logic, a validity verification step is also included: calculate the difference between the maximum and minimum touch values ​​of all buttons in the current scanning cycle. If the difference is less than twice the preset noise threshold, the touch is determined to be valid, so as to execute the state determination logic. Otherwise, this judgment will be abandoned.

9. A disc-type pulley touch detection system for FPC flexible circuit boards, characterized in that, include: The touch-sensitive pulley consists of four touch buttons arranged in a disc-like layout, and is used to enable touch input for products with irregular shapes via a flexible circuit board. The processing control module is configured to perform a disc-type pulley touch detection method for FPC flexible circuit boards as described in any one of claims 1 to 8.

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