CN115499032A - One-to-many UART communication method - Google Patents
One-to-many UART communication method Download PDFInfo
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- CN115499032A CN115499032A CN202211066874.8A CN202211066874A CN115499032A CN 115499032 A CN115499032 A CN 115499032A CN 202211066874 A CN202211066874 A CN 202211066874A CN 115499032 A CN115499032 A CN 115499032A
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
- H04B1/401—Circuits for selecting or indicating operating mode
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04B—TRANSMISSION
- H04B1/00—Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
- H04B1/38—Transceivers, i.e. devices in which transmitter and receiver form a structural unit and in which at least one part is used for functions of transmitting and receiving
- H04B1/40—Circuits
- H04B1/44—Transmit/receive switching
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- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04L—TRANSMISSION OF DIGITAL INFORMATION, e.g. TELEGRAPHIC COMMUNICATION
- H04L2212/00—Encapsulation of packets
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Abstract
The invention discloses a one-to-many UART communication method, which comprises the following steps: a one-to-many UART communication method, comprising: connecting a UART transmitting pin of a main control module with UART receiving pins of a plurality of external modules; the main control module is used for sending the UART communication data to UART receiving pins of the external modules through the UART sending pins of the main control module; further comprising: connecting a UART receiving pin of the main control module with UART transmitting pins of a plurality of external modules; the external module is used for transmitting the UART communication data to a UART receiving pin of the main control module through the UART transmitting pin connection of the external module; the method can realize that the main control end communicates with a plurality of external UART interface modules through one UART.
Description
Technical Field
The invention belongs to the technical field of UART communication, and particularly relates to a one-to-many UART communication method.
Background
With the increasing functions of the embedded device, the number of external modules connected to the main control chip of the embedded device is also increasing. An Asynchronous Receiver Transmitter/Transmitter (UART) is a relatively common hardware interface, and its simple and easy-to-use characteristics make it a first choice when designing a communication interface between a module and a module. However, because the UART itself can only be one-to-one, if a plurality of UART devices are externally connected to the main control chip, a plurality of UART interfaces are required to be provided to connect the UART interface module. The UART resources on the main control chip are limited, the number of the UART resources is about 4, and the number of the UART resources is only 2.
Therefore, how to solve the problem that the master control chip UART is not enough, the master control end communicates with a plurality of external UART interface modules through one UART, which becomes a key problem of current research.
Disclosure of Invention
In view of the above problems, the present invention provides a one-to-many UART communication method that at least solves some of the above technical problems, and provides a technical solution for a main control chip to communicate with a plurality of UART interface modules through a UART.
The embodiment of the invention provides a one-to-many UART communication method, which comprises the following steps: connecting a UART transmitting pin of a main control module with UART receiving pins of a plurality of external modules; the main control module is used for sending UART communication data to the UART receiving pins of the external modules through the UART sending pins of the main control module;
further comprising: connecting a UART receiving pin of a main control module with UART transmitting pins of a plurality of external modules; the external module is used for sending the UART communication data to the UART receiving pin of the main control module through the UART sending pin connection of the external module.
Further, performing a layer of protocol encapsulation on the UART communication data sent by the main control module, wherein the corresponding encapsulation area comprises a data head and a data main body of the UART communication data;
wherein the data header comprises a header identification, a data attribution identification and a data length.
Further, the header identification is set to 2 bytes; setting the data attribution identification to be 1 byte; setting the data length to 2 bytes; the data body is set to a plurality of bytes.
Furthermore, a UART receiving pin of the main control module is connected with UART transmitting pins of a plurality of external modules through a tri-state buffer gate;
when the UART transmitting pin of the external module does not transmit UART communication data, the gateway select of the external module is pulled down through the tri-state buffer gate, so that a TX link of the external module is in a high-impedance state;
when the UART sending pin of the external module needs to send data, the gate select of the external module is pulled high through the tri-state buffer door, so that the TX link of the external module is in a conducting state, the UART sending pin of the external module sends UART communication data, and after the data are sent, the gate select of the external module is pulled low through the tri-state buffer door, so that the TX link of the external module is in a high-resistance state.
Furthermore, at the same time, only one UART transmitting pin of the external module can transmit UART communication data to the UART receiving pin of the main control module.
Further, connecting the function multiplexing pins of the plurality of external modules with each other;
the functional multiplexing pins comprise a TX state pin and a TX select pin;
the TX state pin is used for reading whether other external modules send UART communication data to a UART receiving pin of the main control module;
the TX select pin is used for indicating the external module to send UART communication data to the UART receiving pin of the main control module.
Further, the function multiplexing pin defaults to a TX state function, and at this time, the function multiplexing pin is configured as an input and is pulled down to a low level through a hardware pull-down resistor;
when the external module needs to send UART communication data, the function multiplexing pin is a TX select function, and is configured to output and output a high level; and after the UART communication data is sent, configuring the function multiplexing pin as a TX state function, and converting the function multiplexing pin into a low level state.
Further, performing a layer of protocol encapsulation on the UART communication data sent by the external module, wherein the corresponding encapsulation area comprises a data head and a data main body of the UART communication data; the data head comprises a head mark, a data attribution mark and a data length;
setting the header identification to 2 bytes; setting the data attribution identification to be 1 byte; setting the data length to be 2 bytes; the data body is set to a plurality of bytes.
Compared with the prior art, the one-to-many UART communication method recorded in the invention has the following beneficial effects:
1. the main control module can realize the communication with a plurality of UART interface modules through one UART.
2. The main control module can realize communication only by using TX/RX of UART standard without adding other hardware interfaces.
Additional features and advantages of the invention will be set forth in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
The technical solution of the present invention is further described in detail by the accompanying drawings and embodiments.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
fig. 1 is a schematic design diagram of a one-to-many UART communication method according to an embodiment of the present invention.
Fig. 2 is a schematic diagram of a data transmission flow of the external module according to an embodiment of the present invention.
Fig. 3 is a schematic diagram of a tri-state buffer gate according to an embodiment of the present invention.
Detailed Description
Exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. While exemplary embodiments of the present disclosure are shown in the drawings, it should be understood that the present disclosure may be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the disclosure to those skilled in the art.
Referring to fig. 1, an embodiment of the invention provides a one-to-many UART communication method, including: connecting a UART transmitting pin of a main control module with UART receiving pins of a plurality of external modules; the UART transmitting pin of the main control module is the TX pin of the UART chip in the main control module part in fig. 1; the UART receiving pin of the external module is the RX pin in the external module part in FIG. 1; the main control module is used for sending the UART communication data to UART receiving pins of the plurality of external modules through a UART sending pin of the main control module; the TX pin of the main control module is used as output, the RX pins of other external modules are used as input, one output corresponds to multiple inputs, and there is no conflict in hardware. In order to specify to which external module the data is specifically sent, a layer of protocol encapsulation may be performed on the UART communication data sent by the main control module, which is specifically shown in table 1:
TABLE 1
The embodiment of the invention provides a one-to-many UART communication method, which also comprises the steps of connecting a UART receiving pin of a main control module with UART transmitting pins of a plurality of external modules; the UART receiving pin of the main control module refers to an RX pin of a UART chip in the main control module part in fig. 1; the UART transmitting pin of the external module refers to the TX pin in the external module part in figure 1; the external module is used for transmitting the UART communication data to a UART receiving pin of the main control module through the UART transmitting pin connection of the external module;
in the process of receiving the UART communication data sent by the external module, if the main control module is configured as RX (receiving pin) and other external modules are configured as TX (sending pin) according to the standard configuration of UART, the multiple outputs will affect each other and cannot work normally. In order to solve the problem, a tri-state gate buffer circuit is added, and when the external module does not transmit UART communication data, the gate select of the external module is pulled down through the tri-state buffer circuit, so that a TX link of the external module is set to be in a high-impedance state; when the UART sending pin of the external module needs to send data, the gate select of the external module is pulled up through the tri-state buffer gate, so that the TX link of the external module is in a conducting state, the UART sending pin of the external module sends UART communication data, and after the data sending is finished, the gate select of the external module is pulled down through the tri-state buffer gate, so that the TX link of the external module is in a high-impedance state.
In addition, only one UART transmitting pin of the external module can transmit UART communication data to the UART receiving pin of the main control module at the same time, so that a function multiplexing pin, namely a TX state/select pin, is added for ensuring the synchronization of data transmission states among the external modules. The functional multiplexing pins comprise a TX state pin and a TX select pin; the TX state pin is used for reading whether other external modules send UART communication data to a UART receiving pin of the main control module or not; the TX select pin is used for indicating the external module to send UART communication data to the UART receiving pin of the main control module. The function multiplexing pin defaults to a low level state, and at the moment, the function multiplexing pin is configured to be a TX state pin (namely configured to be in an input state); when the external module needs to send UART communication data, the corresponding function multiplexing pin is configured as a TX select pin (namely configured in an output state), and a high level is output; and after the UART communication data is transmitted, configuring the functional multiplexing pin as a TX state pin, and converting the functional multiplexing pin into a low level state.
When a plurality of external modules send data to the main control module, the output conflict problem among the modules needs to be handled, and the flows of configuration of a TX state/select pin, control of a tri-state buffer gate, data sending and the like are realized according to the flow shown in fig. 2; when the external module does not send data to the main control module, the three-state buffer gate access needs to be closed, and the function multiplexing pin is configured to be in an input state (namely, a TX state pin); if a certain external module (hereinafter referred to as the external module) needs to send data to the main control module, it needs to check whether other external modules are sending data to the main control module, specifically, the TX state/select pin states of other external modules are read, if the external module is at a high level, it indicates that other external modules are sending data to the main control module, and at this time, the external module needs to repeatedly read the TX state/select pin states of other external modules, and until a low level is read, it indicates that other external modules do not send data to the main control module, and at this time, the external module can send data to the main control module;
the specific operation of the external module for sending data is as follows: firstly, configuring a self TX state/select pin into an output state (namely TX select function), converting the output state into a high level state, then pulling up the GateSelect enabling tri-state buffer gate, and pulling down the GateSelect to close the tri-state buffer gate after data transmission is finished.
In addition, in order to determine which external module sends the data specifically, a layer of protocol encapsulation needs to be performed on the UART communication data sent by the external module, and the format of the protocol encapsulation specifically refers to table 2:
TABLE 2
In the embodiment of the invention, the multiplexing of the multi-channel TX signals is mainly realized by adopting a tri-state buffer gate. As shown in fig. 3, the tri-state buffer gate is a key circuit for multiplexing multiple TX signals, and only one TX buffer output of an external module is enabled at a time by control signals 1,2,3, etc., and the others are set to a high impedance state.
It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.
Claims (8)
1. A one-to-many UART communication method, comprising: connecting a UART transmitting pin of a main control module with UART receiving pins of a plurality of external modules; the main control module is used for sending UART communication data to UART receiving pins of the external modules through UART sending pins of the main control module;
further comprising: connecting a UART receiving pin of the main control module with UART transmitting pins of a plurality of external modules; the external module is used for sending the UART communication data to the UART receiving pin of the main control module through the UART sending pin connection of the external module.
2. The one-to-many UART communication method according to claim 1, wherein the UART communication data sent by the main control module is encapsulated by one layer of protocol, and the corresponding encapsulation area comprises a data header and a data body of the UART communication data;
wherein the data header comprises a header identification, a data attribution identification and a data length.
3. The one-to-many UART communication method of claim 2, wherein the header flag is set to 2 bytes; setting the data attribution identification to be 1 byte; setting the data length to 2 bytes; the data body is set to a plurality of bytes.
4. The one-to-many UART communication method according to claim 1, wherein the UART receiving pin of the main control module is connected with the UART transmitting pins of the plurality of external modules through the tri-state buffer gate;
when the UART transmitting pin of the external module does not transmit UART communication data, pulling down the gateway select of the external module through the tri-state buffer gate to enable a TX link of the external module to be in a high-impedance state;
when the UART sending pin of the external module needs to send data, the gate select of the external module is pulled high through the tri-state buffer door, so that the TX link of the external module is in a conducting state, the UART sending pin of the external module sends UART communication data, and after the data are sent, the gate select of the external module is pulled low through the tri-state buffer door, so that the TX link of the external module is in a high-resistance state.
5. The one-to-many UART communication method of claim 1, wherein only one UART transmitting pin of the external module can transmit UART communication data to the UART receiving pin of the main control module at the same time.
6. The one-to-many UART communication method according to claim 5, wherein the function multiplexing pins of the plurality of external modules are connected to each other;
the functional multiplexing pins comprise a TX state pin and a TX select pin;
the TX state pin is used for reading whether other external modules send UART communication data to a UART receiving pin of the main control module;
the TX select pin is used for indicating the external module to send UART communication data to the UART receiving pin of the main control module.
7. The one-to-many UART communication method according to claim 6, wherein the function multiplexing pin defaults to a TX state function, and is configured as an input and is pulled down to a low level by a hardware pull-down resistor;
when the external module needs to send UART communication data, the function multiplexing pin is a TX select function, and the function multiplexing pin is configured to output and output a high level; and after UART communication data transmission is finished, configuring the function multiplexing pin as a TX state function, and converting the function multiplexing pin into a low level state.
8. The one-to-many UART communication method according to claim 1, wherein the UART communication data transmitted by the external module is encapsulated by one layer of protocol, and the corresponding encapsulation area comprises a data header and a data body of the UART communication data; the data head comprises a head mark, a data attribution mark and a data length;
setting the header identification to 2 bytes; setting the data attribution identification to be 1 byte; setting the data length to be 2 bytes; the data body is set to a plurality of bytes.
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