PC Engine TurboGrafx-16 (TG16) emulator is a fork of the excellent PCE.emu.
This is functionally same as PCE.emu but free so that users who don't have access to paid apps (such as Android users in China) can download.
You will find detailed descriptions at the PCE.emu site at
http://www.explusalpha.com/home/pce-emu
Other general information about this emulator is available at
http://www.explusalpha.com/home/general-info
This emulator is under GPL license, You can find the source codes at
https://code.google.com/r/vickvick1337-emu-ex
https://code.google.com/p/emu-ex-plus-alpha
Enjoy!