Communication controller

Abstract

Abstract PURPOSE:To lighten the burden of a upper-order device, by counting the number of received characters, and comparing the number with the specified value, and finding out incorrect data having data length outside the specified value. CONSTITUTION:When a mark signal representing vacancy on a connection line 10 is absent and a data frame is transmitted, a mark detecting circuit 2 starts the operation of a character assembling circuit 3 and a counter 5. A character count control signal generating circuit 4 controls start, stop and comparison of the count of counter 5 with the output of a detection circuit 1 and the mark detection circuit 2 detecting the flag sequence before and after the data frame. A comparison circuit 6 receives the number of received characters in the frame from the counter 5 and compared whether or not the said count value is within the specified value preset in a register 7. If the number of received characters is not within the specified value, the comparison circuit 6 displays the reception of incorrect data and avoids the said incorrect data from being transferred from a buffer memory 8 to an upper-order device.

Inventors

• 👤 Toshihiro Kamiyama
• 👤 神山　敏廣

Bibliographic Details