STMPE1601 STMicroelectronics, STMPE1601 Datasheet - Page 13

• Manufacturer Part Number: STMPE1601
• Description: 16-bit Enhanced Port Expander With Keypad And Pwm Controller Xpander Logic
• Manufacturer: STMicroelectronics

STMPE1601
6.1
6.2
6.3
6.4
6.5
Minimizing current drain on I
The GPIOs 13-15 are used as I
is recommended for these address lines. In the case that these pins are driven to an
opposite logic level during device operation, there would be a current drain of VIO/47K. This
amounts to 70 μA at 3.3 V, 38 μA at 1.8 V for each of the address lines. This is not a small
current for portable devices.
To minimize the current drain on I
1.
2.
3.
Start condition
A Start condition is identified by a falling edge of SDATA while SCLK is stable at high state.
A Start condition must precede any data/command transfer. The device continuously
monitors for a Start condition and does not respond to any transaction unless one is
encountered.
Stop condition
A Stop condition is identified by a rising edge of SDATA while SCLK is stable at high state.
A Stop condition terminates the communication between the slave device and bus master. A
read command that is followed by NoAck can be followed by a Stop condition to force the
slave device into idle mode. When the slave device is in idle mode, it is ready to receive the
next I
operation to the registers.
Acknowledge bit (ACK)
The acknowledge bit is used to indicate a successful byte transfer. The bus transmitter
releases the SDATA after sending eight bits of data. During the ninth bit, the receiver pulls
the SDATA low to acknowledge the receipt of the eight bits of data. The receiver may leave
the SDATA in high state if it would to not acknowledge the receipt of the data.
Data input
The device samples the data input on SDATA on the rising edge of the SCLK. The SDATA
signal must be stable during the rising edge of SCLK and the SDATA signal must change
only when SCLK is driven low.
If maximum keypad size is not required, these shared lines should not be used for
keypad operation.
If the maximum keypad size is required, choose I
all 3 address lines to be pulled to ground, minimizing the current drain in keypad
operation.
In system-controlled idle state, all keypad pins to be configured as hotkey with interrupt
enabled. If any key is pressed, system initiates keypad controller for scanning
operation.
2
C transaction. A Stop condition at the end of a write command stops the write
2
C address input during POR. Pull-up/down resistor of 47 K
2
C lines, a few methods are recommended.
2
C address lines
2
C address 0x40, as this requires that
I2C interface
13/60