Cypress CY4672 manual Modifying the Keyboard Matrix or Adding New Keys

Keyboard

4.4Modifying the Keyboard Matrix or Adding New Keys

The current keyboard matrix with the USB scan codes are shown in Table 4-1 on page 55. Custom- ers may modify the keyboard matrix or they may add new keys to their keyboard. The following sec- tions explain the procedure.

4.4.1Modifying the Keyboard Matrix

In the file kdefs.h, a table called default_keyboard_scan_table matches the keyboard matrix shown in Table 4-1 on page 55. By modifying this table, the keyboard matrix is automatically modified.

4.4.2Adding New Keys

Example

The customer wants to add a multimedia key called ‘My Computer’, which is located at Column 15 and Row 6 and has a scan code of 0x0194. The following steps must be performed:

1.Go to file kdefs.h, and search for default_keyboard_scan_table. In the Col 15 (0xF) section, mod- ify line 7 from {NO_DEVICE, NOKEY} to {DEVICE_2, 0x000E}. The 0x000E is the index into the device 2 table.

2.Go to the table called device_2_keyboard_scan_table within the same file and add the scan code of 0x0194 to the end of the table, as shown:

const UINT16 device_2_keyboard_scan_table[] =

{

0x0192, // Calculator 0x0223, // WWW Home 0x00CD, // Play/Pause 0x0221, // WWW Search 0x018A, // Mail 0x00E9, // Volume Up 0x00E2, // Mute 0x00B7, // Stop 0x00EA, // Volume Down 0x022A, // WWW Favorites 0x0225, // WWW Forward 0x0224, // WWW Back

0x00B6, // Scan Previous Track 0x00B5, // Scan Next Track

0x0194, // My Computer

};

3.Build the firmware, the new key ‘My Computer’ will work.

72 CY4672 Reference Design Guide, Document # 001-16968 Revision **

[+] Feedback