Datasheet

© 2007 Microchip Technology Inc. DS21952B-page 19
MCP23017/MCP23S17
1.6.7 PULL-UP RESISTOR
CONFIGURATION REGISTER
The GPPU register controls the pull-up resistors for the
port pins. If a bit is set and the corresponding pin is
configured as an input, the corresponding port pin is
internally pulled up with a 100 kΩ resistor.
REGISTER 1-7: GPPU – GPIO PULL-UP RESISTOR REGISTER (ADDR 0x06)
R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0 R/W-0
PU7 PU6 PU5 PU4 PU3 PU2 PU1 PU0
bit 7 bit 0
Legend:
R = Readable bit W = Writable bit U = Unimplemented bit, read as ‘0’
-n = Value at POR ‘1’ = Bit is set ‘0’ = Bit is cleared x = Bit is unknown
bit 7-0 PU7:PU0: These bits control the weak pull-up resistors on each pin (when configured as an input)
<7:0>.
1 = Pull-up enabled.
0 = Pull-up disabled.