Ajith, I don't know of any problems of using a lower frequency crystal for this device and we don't specify a lower XTAL frequency for operation. However, there are can be issues with crystal startup and that's why we give recommendations on which crystals to use so that the oscillator startup isn't in question. See page 27 in the datasheet for more details. It is likely that the 16MHz crystal won't be much different than the 16.384MHz crystal for crystals in the same product line. If you test out the crystal and there are issues in the startup, I would start with smaller load capacitances as the board often has some parasitic capacitance adding to the load. However, I think the safest thing would be to use a real clock line, sending in a 16MHz clock into the XTAL1/CLKIN pin instead of using a crystal. Because you're using a different frequency (16MHz instead of 16.384MHz), there will be a modest change in the data rate, and maybe some changes in the clock timing (looking for anything that changes with the clock frequency), but for the most part, the operation should be similar. Joseph Wu
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