Internal Pull-Up Resistors

Discussion created by lpcware Employee on Jun 15, 2016
Latest reply on Jun 15, 2016 by lpcware
Content originally posted in LPCWare by cdoerr on Tue Jul 30 03:25:18 MST 2013

According to the datasheet the LPC1114 (and other LPC microcontroller) have internal pull-up resistors on their GPIO pins. In some forum posts I have however read that these pull-ups are fairly weak. Hence my question: If I want to connect another IC (example below) to these GPIO pins, will the internal pull-ups be sufficient or will I need additional external resistors?


As an example take the MCP73871 charge IC. The datasheet says: "STAT1 is an open-drain logic output for connection to an LED for charge status indication. Alternatively, a pull-up resistor can be applied for interfacing to a host microcontroller."