Key scanning method, scan method for key scan circuit, and input device implemented therewith

A scan method for a key scan circuit capable of scanning a first key group and a second key group, wherein the first key group comprises X priority keys, the second key group comprises Y secondary keys, and the key scan circuit comprises M main scan lines Sa(1) to Sa(M), N secondary scan lines Sb(1) to Sb(N) and a plurality of signal sensing lines, where X, Y, M and N are positive integers, wherein the M main scan lines Sa(1) to Sa(M) are electrically connected to the X priority keys, and the N secondary scan lines Sb(1) to Sb(N) are electrically connected to the Y secondary keys, the scan method comprising:

• step (1), starting a scan cycle and setting an initial value of a main scan count j to 0;
• step (2a), determining whether the main scan count j is equal to a main scan default upper limit Jmax, where Jmax is a positive integer, performing step (3) if yes, and performing step (2b) if no;
• step (2b), sequentially triggering each of the M main scan lines Sa(1) to Sa(M) and reading electrical signals received via the plurality of signal sensing lines to detect whether any of the X priority keys is triggered;
• step (2c), increasing a value of the main scan count j as j=j+1, and returning to step (2a);
• step (3), sequentially triggering non-triggered P secondary scan lines of the N secondary scan lines Sb(1) to Sb(N) and reading the electrical signals received via the plurality of signal sensing lines, wherein the P secondary scan lines are coupled to Q secondary keys of the Y secondary keys to detect whether any of the Q secondary keys is triggered, where P<N and Q<Y, and P and Q are positive integers, wherein at least a next one of the secondary scan lines is non-triggered;
• and
• step (4), during the scan cycle, determining whether all the N secondary scan lines Sb(1) to Sb(N) have been triggered, ending the scan cycle if yes, and setting the main scan count j to 0 and returning to step (2a) if no;
• wherein step (2b) and step (3) are performed one after another for multiple times, until each of the N secondary scan lines is triggered at least once to complete the scan cycle.

An input device, comprising:

• a key scan circuit, comprising M main scan lines Sa(1) to Sa(M), N secondary scan lines Sb(1) to Sb(N), and a plurality of signal sensing lines, where M and N are positive integers;
• a first key group, comprising X priority keys, wherein the M main scan lines Sa(1) to Sa(M) are electrically connected to the X priority keys, where X is a positive integer;
• and
• a second key group, comprising Y secondary keys, wherein the N secondary scan lines Sb(1) to Sb(N) are electrically connected to the Y secondary keys, where Y is a positive integer;
• wherein the key scan circuit performs the following steps:
• step (1), starting a scan cycle and setting an initial value of a main scan count j to 0;
• step (2a), determining whether the main scan count j is equal to a main scan default upper limit Jmax, where Jmax is a positive integer, performing step (3) if yes, and performing step (2b) if no;
• step (2b), sequentially triggering each of the M main scan lines Sa(1) to Sa(M) and reading electrical signals received via the plurality of signal sensing lines to detect whether any of the X priority keys is triggered;
• step (2c), increasing a value of the main scan count j as j=j+1, and returning to step (2a);
• step (3), sequentially triggering non-triggered P secondary scan lines of the N secondary scan lines Sb(1) to Sb(N) and reading the electrical signals received via the plurality of signal sensing lines, wherein the P secondary scan lines are coupled to Q secondary keys among the Y secondary keys to detect whether any of the Q secondary keys is triggered, where P<N and Q<Y, P and Q are positive integers, wherein at least a next one of the secondary scan lines is non-triggered;
• and
• step (4), during the scan cycle, determining whether all the N secondary scan lines Sb(1) to Sb(N) have been triggered, ending the scan cycle if yes, and setting the main scan count j to 0 and returning to step (2a) if no;
• wherein step (2b) and step (3) are performed one after another for multiple times, until each of the N secondary scan lines is triggered at least once to complete the scan cycle.

An input device, comprising:

• a key scan circuit, comprising N+1 scan lines Row 0 to Row N and a plurality of signal sensing lines, where N is a positive integer, wherein the key scan circuit performs following steps:
• step (1), starting a scan cycle, and determining whether the input device is currently in one of a first scan mode, a second scan mode, or a third scan mode to respectively perform one of step (2), step (3) or step (4);
• step (2), when the input device is in the first scan mode, the key scan circuit performing the steps of:
• sequentially triggering one of the plurality of scan lines Row 0 to Row N until each of the plurality of scan lines is triggered, reading electrical signals received via the plurality of signal sensing lines, detecting whether any of a plurality of keys of the input device is triggered, and ending the scan cycle;
• step (3), when the input device is in the second scan mode, the key scan circuit performing the steps of:
• step (3a), defining the scan line Row 0 as a first main scan line Sa(1) and defining the scan lines Row 1 to Row N as N secondary scan lines Sb(1) to Sb(N);
• step (3b), defining X1 keys among the plurality of keys electrically connected to the first main scan line Sa(1) as a first key group, and defining another Y1 keys among the plurality of keys not electrically connected to the first main scan line Sa(1) as a second key group, where X1 and Y1 are positive integers;
• step (3c), setting an initial value of a main scan count j to 0;
• step (3d), determining whether the main scan count j is equal to a preset upper limit Jmax, where the preset upper limit Jmax is a positive integer, performing step (3g) if yes, and performing step (3e) if no;
• step (3e), triggering the first main scan line Sa(1), reading the electrical signals received via the plurality of signal sensing lines, and detecting whether any of the X1 priority keys is triggered;
• step (3f), increasing a value of the main scan count j as j=j+1, and returning to step (3d);
• step (3g), sequentially triggering non-triggered P secondary scan lines among the N secondary scan lines Sb(1) to Sb(N), wherein the P secondary scan lines are coupled to Q secondary keys among the Y1 secondary keys, reading the electrical signals received via the plurality of signal sensing lines, and detecting whether any of the Q secondary keys is triggered, where P<N and Q<Y1, and P and Q are positive integers, wherein at least a next one of the secondary scan lines is non-triggered;
• and
• step (3i), determining whether all the N secondary scan lines Sb(1) to Sb(N) have been triggered, setting the main scan count j to 0 and returning to step (3d) if no, and ending the scan cycle if yes;
• wherein steps (3e) and step (3g) are performed one after another for multiple times, until each of the N secondary scan lines is triggered at least once to complete the scan cycle;
• and
• step (4), when the input device is in a third scan mode, the key scan circuit performing the steps of:
• step (4a), defining the scan lines Row 0 to Row 1 as two main scan lines Sa(1) to Sa(2), and defining the scan lines Row 2 to Row N as N−1 secondary scan lines Sb(1) to Sb(N−1);
• step (4b), defining X2 keys among the plurality of keys electrically connected to the two main scan lines Sa(1) to Sa(2) as a first key group and defining another Y2 keys among the plurality of keys not electrically connected to the two main scan lines Sa(1) to Sa(2) as a second key group, where X2 and Y2 are positive integers;
• step (4c), setting an initial value of a main scan count j to 0;
• step (4d), determining whether the main scan count j is equal to a preset upper limit Jmax, where the preset upper limit Jmax is a positive integer, performing step (4g) if yes, and performing step (4e) if no;
• step (4e), sequentially triggering the two main scan lines Sa(1) to Sa(2), reading the electrical signals received via the plurality of signal sensing lines, and detecting whether any of the X2 priority keys is triggered;
• step (4f), increasing a value of the main scan count j as j=j+1, and returning to step (4d);
• step (4g), sequentially triggering non-triggered P secondary scan lines of the N−1 secondary scan lines Sb(1) to Sb(N-1), wherein the P secondary scan lines are coupled to Q secondary keys among the Y2 secondary keys, reading the electrical signals received via the plurality of signal sensing lines, and detecting whether any of the Q secondary keys is triggered, where P<N−1 and Q<Y2, and P and Q are positive integers, wherein at least a next one of the secondary scan lines is non-triggered;
• and
• step (4h), determining whether all the N−1 secondary scan lines Sb(1) to Sb(N-1) have been triggered, setting the main scan count j to 0 and returning to step (4d) if no, and ending the scan cycle if yes.

A key scanning method, adapted to an input device having a plurality of keys, wherein the input device further has a plurality of scan lines for scanning the plurality of keys and has a plurality of signal sensing lines corresponding to the plurality of keys, and the plurality of scan lines comprise a first main scan line and a plurality of secondary scan lines, wherein the first main scan line is electrically connected to a first key group among the plurality of keys, and the plurality of secondary scan lines are electrically connected to a second key group among the plurality of keys, the key scanning method comprising:

• performing a first scan mode, wherein the first scan mode comprises:
• performing a first scan procedure, wherein the first scan procedure comprises triggering the first main scan line and reading electrical signals received via the plurality of signal sensing lines to determine whether any of the keys among the first key group is triggered;
• and
• performing a second scan procedure, wherein the second scan procedure comprises triggering at least one of the plurality of secondary scan lines and reading the electrical signals received via the plurality of signal sensing lines to determine whether any of the keys among the second key group is triggered;
• wherein the first scan procedure and the second scan procedure are performed one after another, and each of the plurality of secondary scan lines is triggered at least once;
• wherein a number of times that the first main scan line is triggered is at least twice a number of times that each of the plurality of secondary scan line is triggered.