BU8272GUW Datasheet, PDF (12/18 Pages) Rohm – GPIO Expander IC

BU8272GUW
Technical Note
2. GPIOï½¥INT Interface
The default mode of all GPIO [19:0] ports are input mode upon the power-on. By setting the specific bit of Interrupt Mask Sel
register to “1”, the corresponding bit of Interrupt will be masked. There are two kinds of ways to control input / output operations.
The first way is to change read / write register value in each corresponding bit. Second way is to write each GPIO register a “0”
value for ‘Output operation’ and a “1” value for ‘input operation’. It is necessary to pull up the output to the same voltage value
as the corresponding I/O power supply in the second way.
Interrupt Logic
Interrupt Mask
Read Data Register
XRST
Read Configuration
Pulse
Write Configuration
Pulse
GPI Reg
S
Please pull up the output to the same
voltage value as the corresponding I/O
power supply
Data From
Shift Register
GPO Reg
S
Data From
Shift Register
R/W Reg
S
0
1
0
1
IOSEL Reg
GPIO[19:0]
Fig. 13 GPIO・INT system
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12/17
2009.09 - Rev.A