| 摘要 |
<p>PURPOSE:To apply a portable electronic device to various application programs which differ in baud rate and to improve its mass-productivity by setting the baud rate of data transmission and reception optionally according to registered frequency division ratio information. CONSTITUTION:A control element 2 sends selection information stored in a memory 1 to a selecting circuit 7 and also sends the frequency division ratio information to an interface circuit 4. The circuit 7 selects and connects a signal line 6 to an input/output line 11 when the selection information is 0 to enable the element 2 to send and receive data to and from the outside directly. When the select information is 1, on the other hand, a signal line 5 is selected and connected to the line 11 to enable the element 2 to send and receive data to and from the outside through a circuit 4. The circuit 4 receives a clock 10 which is supplied from outside, divides the frequency of the clock 10 by the frequency division ratio information to determine the baud rate of data transmission and reception, and sends and receives the data to and from the outside at the determined rate.</p> |
