Micron Technology Inc., the largest US maker of computer-memory chips, tumbled in late trading after its revenue forecast missed projections by about $1 billion, hurt by sluggish demand for smartphones and personal computers.Sales will be roughly $7.9 billion in the fiscal second quarter, which runs through February, the company said in a statementBloomberg Terminal Wednesday. That compares with an average analyst estimate of $8.99 billion. Profit will be no more than $1.53 a share, minus certai...