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72 CY4672 Reference Design Guide, Document # 001-16968 Revision **
Keyboard
4.4 Modifying 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.
4.4.1 Modifying 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.
4.4.2 Adding 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.
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