External crystal oscillator (ECO) External crystal oscillator (ECO) can use a crystal with frequency ranging from 4 MHz to 36 MHz for generating a high-precision clock. This option can be used when the precision offered by internal oscillators is not sufficient.
但是在老版本的Modustoolbox中，配置ECO的频率为8MHZ的时候，MTB会出现报错：
"'8.0000' is not within the legal range of [16.0000-35.0000] for parameter 'Frequency (MHz)'"
实际上这个频率值是符合要求的，是MTB的personality设置有问题导致的。
