STMPE1801BJR STMicroelectronics, STMPE1801BJR Datasheet - Page 35

• Manufacturer Part Number: STMPE1801BJR
• Description: Touch Screen Converters & Controllers Xpander Logic 18-Bit 18 GPIO 1.65 to 3.6V
• Manufacturer: STMicroelectronics

Specifications of STMPE1801BJR

• Rohs: yes
• Input Type: 1 Keypad
• Data Rate: 400 kbps
• Resolution: 18 bit
• Interface Type: I2C
• Supply Voltage: 1.65 V to 3.6 V
• Supply Current: 28 uA
• Operating Temperature: - 40 C to + 85 C
• Package / Case: CSP-25
• Maximum Operating Temperature: + 85 C
• Minimum Operating Temperature: - 40 C
• Mounting Style: SMD/SMT
• Supply Voltage - Max: 3.6 V
• Supply Voltage - Min: 1.65 V

STMPE1801
11
Keypad controller
The keypad controller consists of:
The key detection priority is dedicated, special function and normal keys.
Four of the row inputs can be configured as dedicated keys through the setting of Dkey0~3
bits of the KPC_CTRL register. The normal key matrix size can be configured through the
setting of KPC_ROW and KPC_COL registers. The scanning of each individual row input
and column output can be enabled or masked to support a key matrix of variable size from 1
x 1 to 10 x 8. It is allowed to have other 8 special function keys incorporated in the key
matrix.
The operation of the keypad controller is enabled by the SCAN bit of KPC_CTRL register.
Every key activity detected is de-bounced for a period set by the DB_1~7 bits of KPC_CTRL
register before a key press or key release is confirmed and updated into the output FIFO.
The key data, indicating the key coordinates and its status (up or down), is loaded into the
FIFO at the end of a specified number of scanning cycles (set by SCAN_COUNT0~3 bits of
KPC_CTRL_MID register). An interrupt is generated when a new set of key data is loaded.
The FIFO has a capacity for ten sets of key data. Each set of key data consists of 5 bytes of
information when any of the four dedicated keys is enabled. It is reduced to 4 bytes when no
dedicated key is involved. When the FIFO is full before its content is read, an overflow signal
is generated while the FIFO will continue to hold its content but forbid loading of new key
data set.
–
–
–
4 dedicated key controllers that support up to 4 simultaneous dedicated key
presses;
a keyscan controller support a maximum of 10 x 8 key matrix with detection of
three simultaneous key presses;
8 special function key controllers that support up to 8 simultaneous “special
function” key presses.
Doc ID 17884 Rev 3
Keypad controller
35/60