My version of AVT1251 kit - HT8955A echo effect.
This project was made just to check, if there is a possibility to connect DRAMs in cascade.
It works with two SMD DRAMs, but it doesn't work with two DIL chips - don't ask me why :)

HT8955A datasheet
AVT1251 article

Eagle files:
echo HT8955A.sch
echo HT8955A.brd