Hi Jeff,

We don't have a driver for the MCP23017 chip, but we can suggest you to use our ADP5589 part. The ADP5589 is a 19 channel GPIO (General Purpose Input/Output) port expander with built-in keypad matrix decoder, programmable logic, reset logic…

Hello Jacky,

The ADP5587 has pull-ups enabled by default on start-up. The maximum recommended sink current is 1mA per pin.

Other chips to consider are the ADP5585, ADP5586, and the ADP5589. These are able to source up to 5 mA and sink up to 10 mA per…

ADP5585相关资料请参考如下链接：http://wiki.analog.com/resources/tools-software/linux-drivers/input-keyboard/adp5589

ADP5585的地址为0x34，但除了ADP5585ACPZ-03-R7（地址为0x30).

我们会联系产品线工程师看是否提供ADP5585的评估板原理图。收到回复后，我们会通过cic.china@analog.com来回复您。

Hello,

1) For the keypad, we don't recommend using RC filters. The pins are well protected from ESD, and as long as the wires running to the KP pins are not ridiculously long, it should be good without filtering.

2) The 100 kΩ resistors are not…