you cannot mine litecoin on a raspberry pi 3....I tried...it wont turn in any valid shares as scrypt algorithm is way too labor intensive for the cpu being there is only 1 gb on ram on it...you can run a usb mining device such as a LKetc off of a raspberry along with gridseeds, zeus' or any other usb mining device....
but if your feelin froggy here is a cpu miner for raspberry that works but I'd recommend mining a coin that works on a cpu better like zcash or monero....there is currently no implementation for the x11 video card on the raspberry that i am aware of anyway...
Raspberry Pi 3 CPU Miner
feel free to check out my new website which is a miner that works on any device that has a web browser:
ADECMiningpool Java Miner
just create an account and I will set you up a page with a personal miner that will mine the Monero blockchain.....and I am paying out (Pay per Hash a.k.a. PPS or pay per share) in Litecoin, Bitcoin or Monero
I connected my Raspberry Pi 3 to my pool last night and it gets a constant 1 hashes per second...(cooling required)
ran it using only 1 core at 50% and it ran great for a long time with no heat issues..only got 0.3 Hashes per second though..so I am getting a heat-sink and fan for it very soon and will have a "USB ASIC Like Miner" that I never have to unplug or shutdown that only uses 10 watss max...
Do NOT Expect a Large Payout from Samller Devices or Slower CPU's
Mining Requires Large amounts of Memory and the Raspbery Pi 3 only has 1 GB of RAM
ADEC Miner works on any Device that has a Web Browser and is connected at a decent WiFi or Ethernet speed
Works Best in Firefox and Google Chrome Browsers