INFORMATION PROCESSOR AND ELECTRONIC DEVICE

摘要

An information processor and an electronic device for transmitting data at high speed, even being of asynchronous type. A microcomputer (140) includes a communication unit (142) which comprises a frequency dividing circuit (146) for diving the frequency of BCLK and generating SMC1 (clock pulses for smapling bits of data transmitted by asynchronous scheme) and a transmitting/receiving circuit (144) for transmitting/receiving data at the timings of SMC1. BCLK is also fed to a debugging tool (150) as a singal from which a frequency dividing circuit (156) generates SMC2. A frequency-division ratio control section (158) changes the frequency-division ratio FD2 depending on the frequency of BCLK, and send the frequency-division ratio data to the communication unit (142). According to the frequency-division data, a frequency-division ratio control section (148) changes the frequency-division ratio FD1 used at the frequency dividing circuit (146). In such a way, data can be transmitted always the most suitably at high transmission speed. BCLK is also used as a clock for sampling trace data in a user's program execution mode.