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CY4672 Reference Design Guide, Document # 001-16968 Revision ** 55
Keyboard
4.2.3 Keyboard Matrix
The PRoC LP RDK keyboard matrix has 18 columns and 8 rows. Key presses generate a GPIO
interrupt when a column is connected (shorted) to a row. The keyboard then scans the matrix to
determine which keys have been pressed.
The RDK keyboard matrix with the USB scan codes are shown in Table 4-1.
Notes:
Yellow indicates Multimedia Key (16-bit value)
Red indicates Power Key
Blue indicates Modifier Key
No color indicates a Standard 101 Key
4.2.4 Hardware Considerations
The keyboard design uses the BAT400D-7-F schottky diode (D1) and CDH53100LC inductor (L3) for
its boost circuitry. These low cost components are used to reduce the over all system cost at the
expense of lower boost efficiency and performance. Preliminary characterization data shows a range
of 68–81% efficiency for the 1.8–2.7V VBAT voltage range at different temperatures (–10C to 80C).
Higher efficiency components such as the ones in the mouse design may be used at the expense of
component costs and board size (these low cost components are smaller in size compared to the
ones used in the mouse design).
Table 4-1. RDK Keyboard Matrix
Row
0
Row
1
Row
2
Row
3
Row
4
Row
5
Row
6
Row
7
Column 0
0x09 0x0A 0x19 0x05 0x17 0x15 0x21 0x22
Column 1
0x0D 0x0B 0x10 0x11 0x1C 0x18 0x24 0x23
Column 2
0x0E 0x3F 0x36 NA 0x30 0x0C 0x25 0x2E
Column 3
0x0F NA 0x37 NA 0x40 0x12 0x26 0x41
Column 4
0x33 0x34 NA 0x38 0x2F 0x13 0x27 0x2D
Column 5
0x31 0x3E 0x28 0x2C 0x2A NA 0x43 0x42
Column 6
0x5A 0x62 0x54 0x4F 0x5D 0x60 0x45 0x49
Column 7
0x59 NA 0x53 0x51 0x5C 0x5F 0x44 0x4C
Column 8
0x5B 0x63 0x55 0x56 0x5E 0x61 0x4E 0x4B
Column 9
0x07 0x3D 0x06 NA 0x3C 0x08 0x20 0x3B
Column 10
0x16 NA 0x1B NA 0x39 0x1A 0x1F 0x3A
Column 11
0x04 0x29 0x1D NA 0x2B 0x14 0x1E 0x35
Column 12
0x58 0x52 0x48 0x50 NA 0x57 0x4D 0x4A
Column 13
NA 0x04 NA 0x40 0x0192 0x47 0x46 0x0223
Column 14
0x02 0x00CD 0x20 NA 0x02 NA 0x0221 0x018A
Column 15
NA NA 0x10 NA 0x00E9 NA NA 0x01
Column 16
0x7D 0x00E2 0x80 0x7C 0x00B7 0x00EA 0x022A NA
Column 17
0x08 0x0225 NA 0x7B 0x0224 0x65 0x00B6 0x00B5
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