Data processing apparatus with circuit for confirming normality of serial transmission data

• US 6,769,039 B2
• Filed: 05/31/2002
• Issued: 07/27/2004
• Est. Priority Date: 06/01/2001
• Status: Expired due to Fees

• Current Assignee: Renesas Electronics Corporation
• Original Assignee: NEC Electronics Corporation (Renesas Electronics Corporation)
• Inventors: Shiraishi, Hidetoshi
• Primary Examiner(s): Fleming, Fritz
• Assistant Examiner(s): CHEN, ALAN S
• Application Number:
  US10/159,500
• Publication Number:
  US 20020184599A1
• Time in Patent Office: 788 Days
• Field of Search: 710/52-57, 710/71, 710/65, 710/58, 710/60, 710/61
• US Class Current: 710/52
• CPC Class Codes: H04L 43/00 Arrangements for monitoring or testing data switching networks
• CPC Class Codes: H04L 43/0847 Transmission error

Abstract

A data processing apparatus has a single serial port, a data transmitting circuit, an output buffer circuit, and a data comparing circuit, and transmits serial data to an external data processing terminal. Serial data to be serially transmitted which is successively generated by the data transmitting circuit is buffered by the output buffering circuit, and serially transmitted from the serial port to the data processing terminal. The data comparing circuit confirms whether serial data transmitted from the data transmitting circuit to the output buffer circuit and serial data transmitted from the output buffer circuit to the serial port agree with each other or not. For example, if a data error occurs in serial data serially transmitted from the data processing apparatus to the data processing terminal due to noise introduced into the serial port, then the data comparing circuit detects that the serial data transmitted from the output buffer circuit to the serial port differs from the serial data transmitted from the data transmitting circuit to the output buffer circuit.

Claims

1. A data processing apparatus for serially transmitting serial data to an external data processing terminal, said apparatus comprising:

a single serial port;

data transmitting means for successively generating serial data to be serially transmitted from said serial port;

output buffer means for buffering serial data successively generated by said data transmitting means and successively transmitting the serial data to said serial port; and

data comparing means for confirming whether serial data transmitted from said data transmitting means to said output buffer means and serial data transmitted from said output buffer means to said serial port agree with each other or not.

2. A data processing apparatus for performing serial communication of serial data bidirectionally with an external data processing terminal, said apparatus comprising:

a single serial port;

data receiving means for successively receiving serial data input from said serial port;

data transmitting means for successively generating serial data to be serially transmitted from said serial port;

output buffer means for buffering serial data successively generated by said data transmitting means and successively transmitting the serial data to said serial port;

a buffer bypass path connected to said serial port parallel to said output buffer means;

connection switching means for selectively connecting said data transmitting means to said output buffer means and connecting said buffer bypass path to said data receiving means; and

data comparing means for confirming whether serial data transmitted from said data transmitting means to said output buffer means and serial data transmitted from said output buffer means to said serial port agree with each other or not.

3. A data processing apparatus according to claim 2, wherein said data receiving means and said data transmitting means comprise single data transmitting means for successively acquiring serial data through said serial port and successively generating serial data to be serially transmitted, and said connection switching means selectively connects said output buffer means and said buffer bypass path to said data transmitting means.

4. A data processing apparatus according to claim 2, wherein said data transmitting means generates returning serial data depending on said serial data serially received through said serial port, and said data comparing means confirms whether said returning serial data agrees with the received serial data.

5. A data processing apparatus according to claim 2, wherein said serial port serially receives said serial data according to T=0 protocol, said data transmitting means generates status data in a receptive state depending on said serial data serially received through said serial port, said connection switching means connects said output buffer means and said data transmitting means to each other in a guard time of said T=0 protocol of the serial data serially received through said serial port, and said data comparing means confirms whether said status data agrees in the guard time of said T=0 protocol.