Asynchronous serial data communication circuits, sensor modules, communication systems, and industrial equipment

Abstract

An asynchronous serial data communication circuit comprising: a clock signal generating unit configured to generate a clock signal; a storage unit configured to store a temperature characteristic of the frequency of the clock signal in a non-volatile manner; and a communication unit configured to perform asynchronous serial data communication on the basis of the clock signal, and to transmit the temperature characteristic of the frequency of the clock signal stored by the storage unit.

Description

[Technical Field]

[0001] The invention disclosed in this specification relates to an asynchronous serial data communication circuit, a sensor module including the asynchronous serial data communication circuit, a communication system including the asynchronous serial data communication circuit, and industrial equipment including the sensor module. [Background technology]

[0002] Conventionally, asynchronous serial data communication has been developed (see, for example, Patent Document 1). In an asynchronous serial data communication circuit, a clock signal is generated on each of the transmitting and receiving sides, and the transmitting circuit operates based on the clock signal generated on the transmitting side, while the receiving circuit operates based on the clock signal generated on the receiving side. A method of asynchronous serial data communication different from that described in Patent Document 1 is start-stop synchronous communication. In start-stop synchronous asynchronous serial data communication, each time one character of character data (e.g., 8-bit data) is sent, a start bit indicating the start of data transmission is added to the beginning of the character data, and a stop bit indicating the end of data transmission is added to the end of the character data.

[0003] In start-stop synchronous asynchronous serial data communication, the receiver detects the start bit sent from the transmitter and receives the data based on a clock signal generated by the receiver itself. Therefore, if one character's worth of character data is 8 bits, for example, if the frequency of the clock signal generated on the transmitter differs by 5% or more, correct communication will not be possible. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2018 / 173623 Summary of the Invention [Problem to be solved by the invention]

[0005] The use of a high-precision clock signal generation circuit can reduce the difference between the frequency of the clock signal generated on the transmitting side and the frequency of the clock signal generated on the receiving side. However, a high-precision clock signal generation circuit is an obstacle to miniaturization and low power consumption of asynchronous serial data communication circuits. [Means for solving the problem]

[0006] The asynchronous serial data communication circuit disclosed in this specification includes a clock signal generating unit configured to generate a clock signal, a memory unit configured to store the temperature characteristic of the frequency of the clock signal in a non-volatile manner, and a communication unit configured to perform asynchronous serial data communication based on the clock signal and to transmit the temperature characteristic of the frequency of the clock signal stored by the memory unit.

[0007] The sensor module disclosed in this specification comprises a sensor and a semiconductor device, and the semiconductor device comprises a driving unit configured to drive the sensor, a processing unit configured to process an output signal of the sensor, and an asynchronous serial data communication circuit having the above-mentioned configuration.

[0008] The communication system disclosed in this specification comprises a first communication circuit and a second communication circuit connected to each other by a signal line, the first communication circuit being configured to adjust the frequency of a clock signal generated within the first communication circuit, and the second communication circuit being an asynchronous serial data communication circuit having the above configuration or an asynchronous serial data communication circuit provided in a sensor module having the above configuration.

[0009] The industrial equipment disclosed in this specification includes a sensor module having the above-described configuration. [Effects of the Invention]

[0010] According to the asynchronous serial data communication circuit, sensor module, communication system, and industrial equipment disclosed in this specification, it is possible to reduce the size and power consumption of the asynchronous serial data communication circuit. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a diagram showing a schematic configuration of a sensor module according to an embodiment. [Figure 2] FIG. 2 is a diagram illustrating an example of the temperature characteristics of the frequency of the clock signal stored in the storage unit. [Figure 3] FIG. 3 is a diagram illustrating a specific example of data stored in the storage unit. [Figure 4] FIG. 4 is a diagram showing the temperature characteristics of the frequency of the clock signal corresponding to FIG. [Figure 5] FIG. 5 is a diagram showing another specific example of data stored in the storage unit. [Figure 6] FIG. 6 is a diagram showing the temperature characteristics of the frequency of the clock signal corresponding to FIG. [Figure 7] FIG. 7 is a diagram illustrating an example of a schematic configuration of a host device. [Figure 8] FIG. 8 is a diagram showing a schematic configuration of an industrial device according to an embodiment. [Figure 9] FIG. 9 is a diagram showing the connection relationship between the host device and a plurality of sensor modules. DETAILED DESCRIPTION OF THE INVENTION

[0012] Fig. 1 is a diagram showing a schematic configuration of a sensor module according to one embodiment. The sensor module 100 shown in Fig. 1 includes a semiconductor device 1, a sensor 2, and terminals T101 to T104.

[0013] The semiconductor device 1 is, for example, an LSI (Large Scale Integration) and includes a clock signal generating unit 10, a digital circuit 11, a driving unit 12, a processing unit 13, a DAC (Digital to Analog Converter) 14, and terminals T11 to T18.

[0014] Sensor 2 collects information about a detection target, converts the collected information into an electrical signal, and outputs it. Sensor 2 has terminals T21 to T24. The detection target of sensor 2 is not particularly limited. The format of the output signal of sensor 2 is not particularly limited, but in this embodiment, sensor 2 outputs a differential voltage signal.

[0015] The terminal T101 is a terminal configured to receive the power supply voltage VDD, and is physically and electrically connected to the terminal T11 inside the sensor module 100.

[0016] The terminal T102 is configured to be connected to the ground potential, and is physically and electrically connected to the terminals T12 and T22 inside the sensor module 100.

[0017] The terminal T103 is a terminal configured to output an output signal of the processing unit 14 (described later) to the outside of the sensor module 100, and is physically and electrically connected to the terminal T16 inside the sensor module 100.

[0018] The terminal T104 is a terminal used for asynchronous serial data communication, and is physically and electrically connected to the terminals T17 and T18 inside the sensor module 100.

[0019] The terminals T13 to T15 are physically and electrically connected to the terminals T21, T23, and T24 inside the sensor module 100, respectively.

[0020] Next, each part of the semiconductor device 1 will be described in detail.

[0021] The clock signal generating unit 10 is an oscillator circuit configured to generate a clock signal. The clock signal generated by the clock signal generating unit 10 is supplied to the digital circuit 11.

[0022] The digital circuit 11 is a circuit that processes digital signals, processes the digital signals at a timing based on the clock signal supplied from the clock signal generating unit 10, and controls the operation of the entire sensor module 100. The digital circuit 11 includes a storage unit 11A, a control unit 11B, and a communication unit 11C.

[0023] The storage unit 11A is configured to store the temperature characteristics of the frequency of the clock signal in a non-volatile manner. As the storage unit 11A, for example, an OTP (One Time Programmable) memory or the like is used.

[0024] As the temperature characteristic of the frequency of the clock signal stored in the storage unit 11A, for example, data such as that shown in Fig. 2 is employed. In the example shown in Fig. 2, "the frequency error of the clock signal generated by the clock signal generating unit 10 at room temperature T1 (for example, 50°C)" is written in advance to an address Ah of the storage unit 11A with a register name M. Also in the example shown in Fig. 2, "the frequency error of the clock signal generated by the clock signal generating unit 10 at high temperature T2 (for example, 150°C)" is written in advance to an address Bh of the storage unit 11A with a register name H. Also in the example shown in Fig. 2, "the frequency error of the clock signal generated by the clock signal generating unit 10 at low temperature T0 (for example, -25°C)" is written in advance to an address Ch of the storage unit 11A with a register name L.

[0025] For example, as shown in Fig. 3, if data "00" is written to address Ah of storage unit 11A with register name M, data "1111" is written to address Bh of storage unit 11A with register name H, and data "1110" is written to address Ch of storage unit 11A with register name L, the temperature characteristics of the frequency of the clock signal stored by storage unit 11A will be as shown by the solid line in Fig. 4. The horizontal axis of the graph shown in Fig. 4 represents temperature, and the vertical axis of the graph shown in Fig. 4 represents the error in the frequency of the clock signal (the error from the design value of the frequency of the clock signal).

[0026] For example, as shown in Fig. 5, if data "11" is written to address Ah of storage unit 11A with register name M, data "0001" is written to address Bh of storage unit 11A with register name H, and data "1111" is written to address Ch of storage unit 11A with register name L, the temperature characteristics of the frequency of the clock signal stored in storage unit 11A will be as shown by the solid line in Fig. 6. The horizontal axis of the graph shown in Fig. 6 represents temperature, and the vertical axis of the graph shown in Fig. 6 represents the error in the frequency of the clock signal (the error from the design value of the frequency of the clock signal).

[0027] Writing data to the memory unit 11A may be achieved, for example, by inputting data from an external device connected to the sensor module 100 via the communication unit 11C before the sensor module 100 is connected to the host device 200, and then writing the data to the memory unit 11A under the control of the control unit 11B.

[0028] The communication unit 11C performs asynchronous serial data communication using start-stop synchronization. A signal transmitted from the communication unit 11C is sent to the host device 200 via terminals T18, T104, and one signal line LN1. Meanwhile, a signal transmitted from the host device 200 is received by the communication unit 11C via one signal line LN1, terminal T104, and terminal T19. An asynchronous serial data communication circuit is configured by the digital circuit 11 including the storage unit 11A and the communication unit 11C, and the clock signal generation unit 10. The asynchronous serial data communication circuit configured by the digital circuit 11 and the clock signal generation unit 10, together with the host device 200, configures a communication system 300.

[0029] The driver 12 is configured to drive the sensor 2. A drive current output from the driver 12 is supplied to a terminal T21 of the sensor 2 via a terminal T13.

[0030] The processing unit 13 is configured to process the output signal of the sensor 2. The processing unit 13 includes a first processing unit 13A and a second processing unit 13B.

[0031] The first processing unit 13A is configured to receive and process the output signal of the sensor 2. Specifically, the output signal of the sensor 2 output from terminals T23 and T24 of the sensor 2 is supplied to the first processing unit 13A via terminals T14 and T15. Although the first processing unit 13A is a single amplifier, the first processing unit 13A is not limited to a single amplifier and may be configured, for example, with a plurality of amplifiers connected in series.

[0032] The second processing unit 13B is configured to receive and process the output signal of the first processing unit 13A. The output signal of the second processing unit 13B is supplied to a terminal T103 via a terminal T16. In FIG. 1, the second processing unit 13B is a single amplifier, but the second processing unit 13B is not limited to a single amplifier and may be configured, for example, with a plurality of amplifiers connected in series.

[0033] The control unit 11B is 4The output offset of the driver 12 is corrected by controlling the driver 12 via the

[0034] Next, a description will be given of the host device 200. Fig. 7 is a diagram showing an example of a schematic configuration of the host device 200. The host device 200 shown in Fig. 7 is a microcomputer having a start-stop synchronous asynchronous serial data communication function.

[0035] The host device 200 shown in FIG. 7 includes a communication unit 201, a control unit 202, a storage unit 203, and a clock signal generation unit 204 with a frequency adjustment function (hereinafter abbreviated as "clock signal generation unit 204").

[0036] A CPU (Central Processing Unit), for example, is used as the control unit 202. The control unit 202 processes digital signals at a timing based on a clock signal output from a clock signal generation unit 204, and executes a program stored in a storage unit 203 to control the overall operation of the host device 200. The communication unit 201 uses the clock signal output from the clock signal generation unit 204 to perform start-stop synchronous asynchronous serial data communication.

[0037] The control unit 202 adjusts the frequency of the clock signal by controlling the clock signal generating unit 204. For example, if the clock signal generating unit 204 includes a PLL (Phase Locked Loop) circuit, the control unit 202 adjusts the frequency of the clock signal by controlling the division ratio of a frequency divider in the PLL circuit.

[0038] The control unit 202 adjusts the frequency of the clock signal (the clock signal generated by the clock signal generating unit 204) according to the temperature characteristics of the frequency of the clock signal (the clock signal generated by the clock signal generating unit 10) sent from the sensor module 100.

[0039] Specifically, at room temperature T1, where normal communication is guaranteed when the frequency of the clock signal generated by the clock signal generating unit 204 is at its initial value, the host device 200 transmits a transmission request regarding the temperature characteristics of the frequency of the clock signal to the sensor module 100, and when the transmission request is received by the communication unit 11C in the sensor module 100, the temperature characteristics of the frequency of the clock signal (the clock signal generated by the clock signal generating unit 10) are transmitted from the communication unit 11C to the communication unit 201.

[0040] For example, in start-stop synchronous asynchronous serial data communication executed between communication unit 11C and communication unit 201, if character data for one character is 8-bit data, clock signal generation units 10 and 204 are designed so that the frequency of the clock signal generated by clock signal generation unit 10 and the initial value of the frequency of the clock signal generated by clock signal generation unit 204 do not deviate by 5% or more at room temperature T1.

[0041] The expected temperature during use is stored in advance in the storage unit 203. In other words, the host device 200 acquires information about the expected temperature during use in advance.

[0042] For example, in start-stop synchronous asynchronous serial data communication executed between communication unit 11C and communication unit 201, if character data for one character is 8-bit data, control unit 202 controls clock signal generation unit 204 so that the frequency of the clock signal generated by clock signal generation unit 10 and the frequency of the clock signal generated by clock signal generation unit 204 do not deviate by 5% or more at the expected temperature during use.

[0043] When the assumed temperature during use is neither the high temperature T2 nor the low temperature T0, the control unit 202 may perform linear interpolation as shown by the dotted lines in Figures 4 and 6 to estimate the error in the frequency of the clock signal (the clock signal generated by the clock signal generating unit 10) at the assumed temperature during use.

[0044] As described above, in this embodiment, the frequency of the clock signal (the clock signal generated by the clock signal generating unit 204) sent from the sensor module 100 is adjusted according to the temperature characteristics of the frequency of the clock signal (the clock signal generated by the clock signal generating unit 10). Therefore, the clock signal generating unit 10 does not need to be a highly accurate clock signal generating unit, and the clock signal generating unit 10 can be made simple and compact. This makes it possible to reduce the size and power consumption of the asynchronous serial data communication circuit formed by the digital circuit 11 and the clock signal generating unit 10.

[0045] There is no limitation on the device or equipment in which the above-described sensor module 100 is mounted. That is, the sensor module 100 may be mounted, for example, in industrial equipment or consumer equipment.

[0046] The sensor module 100 is mounted on, for example, FA (Factory Automation) equipment 400 shown in FIG. 8. That is, the FA equipment 400 includes the sensor module 100. The FA equipment 400 further includes a control unit 401 and a storage unit 402. The control unit 401 controls the entire FA equipment 400 based on a program stored in the storage unit 402. The control unit 401 executes various information processing based on the output signal of the sensor module 100. The FA equipment 400 is connected to machines that make up a production facility. Note that examples of industrial equipment other than the FA equipment 400 include a solar power generation system and a fuel cell.

[0047] In addition to the above-described embodiments, various modifications can be made to the configuration of the present invention without departing from the spirit of the invention. The above-described embodiments are illustrative in all respects and should be considered not to be limiting. The technical scope of the present invention is defined by the claims, not by the description of the above-described embodiments, and should be understood to include all modifications that fall within the meaning and scope of the claims.

[0048] For example, in the above-described embodiment, one sensor module 100 is connected to one host device 200 by one signal line LN1, but as shown in Fig. 9, a configuration may also be adopted in which multiple sensor modules 100 are each connected to one host device 200 by one signal line. Also, for example, in the communication system 300 shown in Fig. 1, one signal line is provided between the sensor module 100 and the host device 200, but a signal line for transmitting data from the sensor module 100 to the host device 200 and a signal line for transmitting data from the host device 200 to the sensor module 100 may be provided.

[0049] For example, in the above-described embodiment, the host device 200 acquires information about the expected temperature during use. However, the host device 200 may also acquire information about the ambient temperature. The ambient temperature information may be detected by a temperature sensor built into the host device 200 or by a temperature sensor externally attached to the host device 200. In this case, the temperature sensor built into the host device 200 or the temperature sensor externally attached to the host device 200 is located at a location with the same temperature as the sensor module 100. For example, in asynchronous serial data communication performed between the communication unit 11C and the communication unit 201, if character data for one character is 8-bit data, the control unit 202 may control the clock signal generation unit 204 so that the frequency of the clock signal generated by the clock signal generation unit 10 and the frequency of the clock signal generated by the clock signal generation unit 204 do not deviate by 5% or more at the ambient temperature. This makes it possible to ensure normal communication in real time in the asynchronous serial data communication performed between the communication unit 11C and the communication unit 201.

[0050] For example, in the above-described embodiment, the temperature characteristics of the frequency of the clock signal stored by the memory unit 11A were information indicating the relationship between a plurality of different temperatures (e.g., room temperature T1, high temperature T2, and low temperature T0) and the frequency of the clock signal, but it may also be information indicating the relationship between a single temperature (e.g., the expected temperature during use) and the frequency of the clock signal.

[0051] For example, when controlling the drive current of sensor 2 to be constant, a current sensing resistor through which the drive current of sensor 2 flows is added to sensor module 100, and the current sensing resistor converts the drive current of sensor 2 into a voltage, and the voltage corresponding to the drive current of sensor 2 is fed back to drive unit 12.

[0052] The asynchronous serial data communication circuit (10, 11) described above has a configuration (first configuration) including a clock signal generation unit (10) configured to generate a clock signal, a memory unit (11A) configured to store the temperature characteristics of the frequency of the clock signal in a non-volatile manner, and a communication unit (11C) configured to perform asynchronous serial data communication based on the clock signal and to transmit the temperature characteristics of the frequency of the clock signal stored in the memory unit.

[0053] The asynchronous serial data communication circuit having the first configuration does not require a highly accurate clock signal generating section, and the clock signal generating section can be made simple and small, thereby enabling miniaturization and low power consumption.

[0054] In the asynchronous serial data communication circuit of the first configuration described above, the communication unit may be configured (second configuration) to transmit the temperature characteristic of the frequency of the clock signal stored by the memory unit when receiving a transmission request regarding the temperature characteristic of the frequency of the clock signal.

[0055] In the asynchronous serial data communication circuit having the second configuration, the temperature characteristics of the frequency of the clock signal stored in the storage unit can be easily extracted from the asynchronous serial data communication circuit.

[0056] In the asynchronous serial data communication circuit having the first or second configuration, the temperature characteristic of the frequency of the clock signal stored by the memory unit may be configured (third configuration) to be information indicating the relationship between a plurality of different temperatures and the frequency of the clock signal.

[0057] The asynchronous serial data communication circuit having the third configuration can transmit the temperature characteristics of the frequency of the clock signal over a wide temperature range.

[0058] In the asynchronous serial data communication circuit having the first or second configuration, the temperature characteristic of the frequency of the clock signal stored by the memory unit may be configured (fourth configuration) to be information indicating the relationship between a single temperature and the frequency of the clock signal.

[0059] The asynchronous serial data communication circuit having the fourth configuration can suppress the amount of transmitted information about the temperature characteristics of the frequency of the clock signal.

[0060] The sensor module (100) described above includes a sensor (2) and a semiconductor device (1), and the semiconductor device has a configuration (fifth configuration) including a drive unit (12) configured to drive the sensor, a processing unit (14) configured to process an output signal of the sensor, and an asynchronous serial data communication circuit having any of the first to fourth configurations described above.

[0061] In the sensor module having the fifth configuration, the asynchronous serial data communication circuit can be made smaller and consume less power.

[0062] The communication system (300) described above comprises a first communication circuit (200) and a second communication circuit connected to each other by a signal line, the first communication circuit being configured to adjust the frequency of a clock signal generated within the first communication circuit, and the second communication circuit being an asynchronous serial data communication circuit having any of the first to fourth configurations or an asynchronous serial data communication circuit provided in a sensor module having the fifth configuration (sixth configuration).

[0063] In the communication system having the sixth configuration, the asynchronous serial data communication circuit can be made smaller and consume less power.

[0064] In the communication system having the sixth configuration described above, the first communication circuit may be configured to acquire information about an expected temperature during use and adjust the frequency of a clock signal generated within the first communication circuit in accordance with the information about the expected temperature during use (seventh configuration).

[0065] The communication system having the seventh configuration can ensure normal communication at the expected temperature during use.

[0066] In the communication system of the sixth configuration, the first communication circuit may be configured to acquire ambient temperature information and adjust the frequency of a clock signal generated within the first communication circuit in accordance with the ambient temperature information (eighth configuration).

[0067] The communication system having the eighth configuration can ensure normal communication depending on the ambient temperature.

[0068] The industrial equipment (400) described above has a configuration (ninth configuration) including the sensor module of the fifth configuration.

[0069] The industrial equipment having the ninth configuration can achieve miniaturization and low power consumption of the asynchronous serial data communication circuit. [Explanation of symbols]

[0070] 1. Semiconductor device 10 Clock signal generation unit 11 Digital Circuits 11A Storage section 11B Control section 11C Communication Department 12 Drive unit 13 Processing section 13A First processing section 13B Second Processing Section 14 DAC 2 sensors 100 Sensor Module 200 Host Device 201 Communications Department 202 Control section 203 Storage section 204 Clock signal generator with frequency adjustment function 300 Communication Systems 400 FA equipment 401 Control Unit 402 Storage section LN1 signal line T11~T18, T21~T24, T101~T104 terminals

Claims

1. a clock signal generator configured to generate a clock signal; a storage unit configured to store the temperature characteristic of the frequency of the clock signal in a non-volatile manner; a communication unit configured to perform asynchronous serial data communication based on the clock signal and to transmit the temperature characteristic of the frequency of the clock signal stored in the storage unit; Equipped with The asynchronous serial data communication circuit, wherein the communication method of the asynchronous serial data communication is start-stop synchronization.

2. 2. The asynchronous serial data communication circuit according to claim 1, wherein the communication unit is configured to transmit the temperature characteristics of the frequency of the clock signal stored by the storage unit when receiving a transmission request regarding the temperature characteristics of the frequency of the clock signal.

3. 2. The asynchronous serial data communication circuit according to claim 1, wherein the temperature characteristics of the frequency of the clock signal stored in the storage unit are information indicating a relationship between a plurality of different temperatures and the frequency of the clock signal.

4. 2. The asynchronous serial data communication circuit according to claim 1, wherein the temperature characteristic of the frequency of the clock signal stored in the storage unit is information indicating a relationship between a single temperature and the frequency of the clock signal.

5. a sensor and a semiconductor device; The semiconductor device includes: a driver configured to drive the sensor; a processing unit configured to process an output signal of the sensor; an asynchronous serial data communication circuit according to claim 1; A sensor module comprising:

6. a first communication circuit and a second communication circuit connected to each other by a signal line; the first communication circuit is configured to adjust the frequency of a clock signal generated inside the first communication circuit; A communication system, wherein the second communication circuit is the asynchronous serial data communication circuit according to any one of claims 1 to 4 or the asynchronous serial data communication circuit included in the sensor module according to claim 5.

7. A communication device comprising a first communication circuit and a second communication circuit connected to each other by a signal line, the first communication circuit is configured to adjust the frequency of a first clock signal generated within the first communication circuit; The second communication circuit a clock signal generator configured to generate a second clock signal; a storage unit configured to store the temperature characteristic of the frequency of the second clock signal in a non-volatile manner; a communication unit configured to perform asynchronous serial data communication based on the second clock signal and to transmit the temperature characteristic of the frequency of the second clock signal stored in the storage unit, A communication system, wherein the first communication circuit is configured to acquire information about an expected temperature during use, and adjust a frequency of the first clock signal in accordance with the information about the expected temperature during use.

8. A communication device comprising a first communication circuit and a second communication circuit connected to each other by a signal line, the first communication circuit is configured to adjust the frequency of a first clock signal generated within the first communication circuit; The second communication circuit a clock signal generator configured to generate a second clock signal; a storage unit configured to store the temperature characteristic of the frequency of the second clock signal in a non-volatile manner; a communication unit configured to perform asynchronous serial data communication based on the second clock signal and to transmit the temperature characteristic of the frequency of the second clock signal stored in the storage unit, The first communication circuit is configured to obtain ambient temperature information and adjust a frequency of the first clock signal in response to the ambient temperature information.

9. An industrial device comprising the sensor module according to claim 5 .

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