Semiconductor device operating according to an operation clock and having a serial communication interface performing external communications according to a unit transfer time based on the operation clock

A semiconductor device that operates according to a certain operation clock, comprising:

• a serial communication interface that performs serial communication with outside, according to a unit transfer time based on the operation clock,
• wherein the serial communication interface includes:
• a baud rate generator that generates a basic clock for counting the operation clock to define the unit transfer time, based on a result of the count;
• a transmission/reception controller that controls transmission and reception according to the basic clock generated by the baud rate generator;
• and
• a bit rate modulator capable of realizing a desired bit rate by partially masking supply of the operation clock to the baud rate generator, according to preset information, and
• wherein the bit rate modulator includes:
• a first counter that counts the operation clock;
• a weight reversing circuit that reverses a weight for output bits of the first counter;
• a first register that allows information for determining a duty of the basic clock to be set;
• a first comparator that compares an output of the weight reversing circuit with an output of the first register;
• and
• a logic gate that partially masks the supply of the operation clock to the baud rate generator by performing logical operation between a result of comparison by the comparator and the operation clock.