KPIC-2840p board using a 40x2 chip

[michael boyd]

I am making a board using a 40x2 chip.
I have completed the download circuit ( consisting of stereo plug and 10 and 22K resistors) and the reset circuit

In the programming manual, this suits the minimum requirements but in my 28 PIN PROJECT BOARD brochure that came with it, shows all the INPUT pins connected to 0v via 10K resisters.

Do I need these resistors or anything else to prevent damage to the chip and to make it work?

In my project, when it is finished there will be alot of spare inputs/outputs

 

[BeanieBots]

Pulldown resistors on unused inputs are not REQUIRED but it is a good idea to fit them.
Your 40X2 will not be damaged without them but the inputs will float causing higher currents to be used by the chip and potentially could result in spurious behaviour if any of your code references any of the unused pins.

You should also fit a 100nF decoupling capacitor close to the power pins.

 

[westaust55]

IMHO leave out the pull down resistors from a general purpose/experimentation board.

Your program code should only be referencing input pins that are used and properly "conditioned" with signals from other devises including, if necessary, pull up or pull down resistors relevant to that signal/device.

Having permanently installed pull-down resistors can be a pain as many have found with the Rev Ed project boards when the need arises to remove some to use specific devices - for example the DS18B20 uses a 4.7k Ohm pull up.