Datasheet
Device
Keyboardcontroller
kbd_r_0
kbd_c_0
VCC
Internal
pullup
kbd_r_1
kbd_r_2
kbd_r_3
kbd_r_4
kbd_r_5
kbd_c_1
kbd_c_2
kbd_c_3
kbd_c_4
kbd_c_5
6x6
Keyboardmatrix
037-014
TPS65930/TPS65920
SWCS037G–MAY 2008– REVISED APRIL 2011
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10 Keyboard
10.1 Keyboard Connection
The keyboard is connected to the chip using:
• KBR (5 :0) input pins for row lines
• KBC (5 :0) output pins for column lines
Figure 10-1 shows the keyboard connection.
Figure 10-1. Keyboard Connection
When a key button of the keyboard matrix is pressed, the corresponding row and column lines are shorted
together. To allow key press detection, all input pins (KBR) are pulled up to V
CC
and all output pins (KBC)
are driven to a low level.
Any action on a button generates an interrupt to the sequencer.
The decoding sequence is written to allow detection of simultaneous press actions on several key buttons.
The keyboard interface can be used with a smaller keyboard area than 6 × 6. To use a 3 × 3 keyboard,
KBR(4) and KBR(5) must be tied high to prevent any scanning process distribution.
82 Keyboard Copyright © 2008–2011, Texas Instruments Incorporated
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