US 2013/0259095 A1 · MODBUS REPEATER WITH SELF-ADAPTIVE BAUD RATE AND SELF-ADAPTIVE BAUD RATE SYTEM AND METHOD

Abstract

Disclosed are a self-adaptive baud rate system and method. The method includes: a) receiving first data and second data; b) judging whether or not a falling edge of a start bit in a synchronization code of the first data and second data is detected; c) if the falling edge is not detected, then return to step b); and if the falling edge is detected, then a first counting is started from a rising edge after the start bit based on a reference clock, and stopped at the next falling edge, and a first count value is obtained; and a second counting is started from the falling edge where the first counting was stopped, and stopped at the next rising edge, and a second count value is obtained; and d) acquiring a baud rate according to the relationships among the first count value and the second count value and a first threshold. By way of using a CPLD to detect the baud rate and encoding format of a Modbus data frame remotely according to the present application, there is no need to manually set the baud rate and encoding format locally. The function of remote auto-detection of the baud rate and encoding format can be achieved by the present application, and the materials and assembly costs of the rotary encoder are omitted.

Claims17

Dependent claims

A self-adaptive baud rate method, comprising the steps of:

a) receiving first data and second data;
b) determining whether or not a falling edge of a start bit in a synchronization code of the first data and second data is detected;
c) if the falling edge is not detected, returning to step b);
if the falling edge is detected, starting a first counting from a rising edge following the start bit based on a reference clock, stopping the first counting at a next falling edge, and obtaining a first count value;
starting a second counting from the falling edge where the first counting was stopped, and stopping the second counting at a next rising edge, and obtaining a second count value;
and
d) obtaining a baud rate according to the relation between the first count value and the second count value and a first threshold.

4 more elements

A self-adaptive baud rate system, comprising:

a first digital filter configured to receive first data from a first transceiver;
a second digital filter configured to receive second data from a second transceiver;
a frequency divider configured to output a reference clock to a first counter and a second counter according to an external crystal oscillator;
the first counter configured to count the first data and the second data based on the reference clock, and obtain a first count value and a second count value;
a baud rate detection unit configured to receive the first data and the second data from the first digital filter and the second digital filter, when detecting a falling edge of a start bit in a synchronization code of the first data and the second data, control the first counter to start a first counting from a rising edge following the start bit and stop the first counting at a next falling edge and obtain the first count value;
control the first counter to start a second counting from the falling edge where the first counting was stopped until a next rising edge, and obtain the second count value;
and obtain a baud rate according to the relation between the first count value and the second count value and a first threshold;
the second counter configured to perform a third counting on the first data and the second data based on the reference clock, and obtain a third count value;
a baud rate generator configured to control an output control unit and the second counter according to the baud rate and the encoding format detected by the baud rate detection unit together with the first data and second data;
the output control unit configured to output a first enable signal or a second enable signal under the control of the second counter and the baud rate generator.

7 more elements

Dependencies are inferred from the claim text.

Modbus repeater with self-adaptive baud rate and self-adaptive baud rate sytem and method

Life of this patent

Modbus repeater with self-adaptive baud rate and self-adaptive baud rate sytem and method

Life of this patent

Abstract

Claims17