STEVAL-TCS003V1 STMicroelectronics, STEVAL-TCS003V1 Datasheet - Page 47

• Manufacturer Part Number: STEVAL-TCS003V1
• Description: BOARD DEMO EXPANDER STMPE2403
• Manufacturer: STMicroelectronics

Specifications of STEVAL-TCS003V1

• Main Purpose: Interface, GPIO Expander
• Embedded: No
• Utilized Ic / Part: STMPE2403
• Primary Attributes: 8/16/24-Bit 24-Port GPIO Expander over I2C
• Secondary Attributes: 3 8-Bit PWM Output for LEDs, Keyboard Matrix Scan, Special Key Support
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Other names: 497-8206

STMPE2403
12.1
The keypad column inputs enabled by the KPC_col register are normally 'HIGH', with the
corresponding input pins pulled up by resistors internally. After reset, all the keypad row
outputs enabled by the KPC_row register are driven 'LOW'. If a key is pressed, its
corresponding column input will become 'LOW' after making contact with the 'LOW' voltage
on its corresponding row output.
Once the key scan controller senses a 'LOW' input on any of the column inputs, the
scanning cycles will then start to determine the exact key that has been pressed. The twelve
row outputs will be driven 'LOW' one by one during each scanning cycle. While one row is
driven 'LOW', all other rows are in tri-state and pulled up. If there is any column input sensed
as 'LOW' when a row is driven 'LOW', the key scan controller will then decode the key
coordinates (its corresponding row number and column number), save the key data into a
de-bounce buffer if available, confirm if it is a valid key press after de-bouncing, and update
the key data into output data FIFO if valid.
Keypad configurations
The keypad controller supports the following types of keys
Figure 9.
–
–
–
Up to 8 Input *12 Output Matrix Keys
Up to 8 Special Function Keys
Up to 4 Dedicated Keys
STMPE2403
Maximum configuration
Input 0-7
8*12 (96) Matrix Keys
8 Special Function Keys
0 Dedicated Keys
Special Function Keys
Matrix Keypad
(8*12)
Keypad controller
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