Cypress CY4672 manual Keyboard Matrix, Row

Keyboard

4.2.3Keyboard 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.

Table 4-1. RDK Keyboard Matrix

	Row	Row	Row	Row	Row	Row	Row	Row
	0	1	2	3	4	5	6	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
Notes:

Yellow indicates Multimedia Key (16-bit value)

Red indicates Power Key

Blue indicates Modifier Key

No color indicates a Standard 101 Key

4.2.4Hardware 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).

CY4672 Reference Design Guide, Document # 001-16968 Revision ** 55

[+] Feedback