请问LVCOMS 和 HCMOS 电平的主要区别是什么

简单来说，LVCMOS一般最高可以接3.3V，HCMOS一般可以最高接5.5V。
HCMOS stands for High Speed CMOS and is a higher speed variant on the original CMOS – the terms HCMOS and CMOS are often interchangeable in the oscillator world.
LVCMOS stands for Low Voltage CMOS and as its name suggests it is a low voltage class of CMOS.
更多知识
http://en.wikipedia.org/wiki/HCMOS
http://en.wikipedia.org/wiki/LVCMOS