CN117194307A - Single-wire communication method based on CamerLink interface - Google Patents
Single-wire communication method based on CamerLink interface Download PDFInfo
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- CN117194307A CN117194307A CN202311093556.5A CN202311093556A CN117194307A CN 117194307 A CN117194307 A CN 117194307A CN 202311093556 A CN202311093556 A CN 202311093556A CN 117194307 A CN117194307 A CN 117194307A
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Abstract
The invention belongs to the technical field of communication, and discloses a single-wire communication method based on a CamerLink interface, which comprises the following steps: s1, a transmission end is connected with a receiving end through a signal port, the transmission end controls the level of the signal port, and the receiving end detects the edge and the state of the signal port; s2, starting transmission, wherein the signal port is at a low level and has a duration of T1; s3, carrying out specific transformation on the level at the signal port, and detecting the high level duration Th and the low level duration Tl between two rising edges of the signal port by the receiving end, wherein if Th >2Tl indicates that 1 is received, and if 2Th < Tl indicates that 0 is received; and S4, ending transmission, wherein the signal port is at a high level and has a duration of T2. The invention has the beneficial effects that: the data communication is realized by utilizing the CameraLink idle data channel, so that one-to-many unit selection can be realized by using a one-way communication protocol between the host and each processing unit.
Description
Technical Field
The invention relates to the technical field of communication, in particular to a single-wire communication method based on a CamerLink interface.
Background
The CameraLink is developed from the Channel link technology, and transmission control signals are added on the basis of the Channel link technology, and relevant transmission standards are defined to be customized, modified and released by AIA of the American automatic industry Association. In order to effectively reduce the comprehensive cost of an image acquisition processing system, and enable embedded processing of images to be possible along with the development of embedded processing, under the condition that embedded processing modules are cascaded through a CameraLink interface, each processing module needs to be accessed and data output in a specific mode, and under the condition that no additional hardware equipment is added, how to achieve the technical aim by utilizing the existing software and hardware resources is a problem to be solved.
The embedded or single-board multi-system communication technology is mainly a two-wire, three-wire or multi-wire system communication mode, and the communication mode has certain advantages, such as the characteristics of simple protocol, simple circuit, duplex or simplex, etc., and in some special scenes, particularly in specific application scenes, the existing electrical channel is utilized to achieve data transmission, and the upper computer cannot realize standard protocol or is complex to realize, so that the mode cannot be applied. In the existing various bus technologies, for example, RS232 needs to have strict timing control, for example, I2C needs to synchronize clocks, for example, SPI needs to synchronize clocks, so that in the downstream channel of the camellink, such standard communication buses cannot be used.
Therefore, it is necessary to provide a single-wire communication method based on the camellink interface, which uses the camellink idle data channel to realize data communication, so as to realize one-to-many unit selection by using the unidirectional communication protocol between the host and each processing unit.
Disclosure of Invention
The invention discloses a single-wire communication method based on a CamerLink interface, which can effectively solve the technical problems related in the background technology.
In order to achieve the above purpose, the technical scheme of the invention is as follows:
a single-wire communication method based on a CamerLink interface comprises the following steps:
s1, a transmission end is connected with a receiving end through a signal port, the transmission end controls the level of the signal port, and the receiving end detects the edge and the state of the signal port;
s2, starting transmission, wherein the signal port is at a low level and has a duration of T1;
s3, carrying out specific transformation on the level at the signal port, and detecting the high level duration Th and the low level duration Tl between two rising edges of the signal port by the receiving end, wherein if Th >2Tl indicates that 1 is received, and if 2Th < Tl indicates that 0 is received;
and S4, ending transmission, wherein the signal port is at a high level and has a duration of T2.
As a preferred improvement of the present invention: t1 is 1s.
As a preferred improvement of the present invention: and T2 is 1s.
As a preferred improvement of the present invention: when data 0 is transmitted, th=0.2s, t1=0.6s.
As a preferred improvement of the present invention: when data 1 is transmitted, th=0.6s, t1=0.2 s.
The beneficial effects of the invention are as follows:
the single line transmission method is used in cascade connection of CameraLink bus, and is used in unidirectional communication protocol between host and each processing unit to realize one-to-many unit selection.
Drawings
For a clearer description of the technical solutions of the embodiments of the present invention, the drawings that are needed in the description of the embodiments will be briefly introduced below, it being obvious that the drawings in the description below are only some embodiments of the present invention, and that other drawings can be obtained according to these drawings without inventive effort for a person skilled in the art, wherein:
FIG. 1 is a block diagram of a circuit configuration;
FIG. 2 is a bit-defined waveform;
fig. 3 is an example byte waveform.
Detailed Description
The technical solutions of the embodiments of the present invention will be clearly and completely described in the following in conjunction with the embodiments of the present invention, and it is obvious that the described embodiments are only some embodiments of the present invention, but not all embodiments. All other embodiments, which can be made by those skilled in the art based on the embodiments of the invention without making any inventive effort, are intended to be within the scope of the invention.
It should be noted that all directional indicators (such as up, down, left, right, front, and rear … …) in the embodiments of the present invention are merely used to explain the relative positional relationship, movement, etc. between the components in a particular posture (as shown in the drawings), and if the particular posture is changed, the directional indicator is changed accordingly.
Furthermore, descriptions such as those referred to as "first," "second," and the like, are provided for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implying an order of magnitude of the indicated technical features in the present disclosure. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In the description of the present invention, the meaning of "plurality" means at least two, for example, two, three, etc., unless specifically defined otherwise.
In the present invention, unless specifically stated and limited otherwise, the terms "connected," "affixed," and the like are to be construed broadly, and for example, "affixed" may be a fixed connection, a removable connection, or an integral body; can be mechanically or electrically connected; either directly or indirectly, through intermediaries, or both, may be in communication with each other or in interaction with each other, unless expressly defined otherwise. The specific meaning of the above terms in the present invention can be understood by those of ordinary skill in the art according to the specific circumstances.
In addition, the technical solutions of the embodiments of the present invention may be combined with each other, but it is necessary to be based on the fact that those skilled in the art can implement the technical solutions, and when the technical solutions are contradictory or cannot be implemented, the combination of the technical solutions should be considered as not existing, and not falling within the scope of protection claimed by the present invention.
Referring to fig. 1, the device of the present embodiment may include a host, a CameraLink acquisition card, a CameraLink cable, a CameraLink processing unit 1, a CameraLink cable, a CameraLink processing unit 2 … …, and a CameraLink processing unit 16, and the circuit structure block diagram is shown in fig. 1. And receiving N-bit transmission data through a single wire, wherein the N-bit data triggers transmission by a characteristic initial signal, and represents that the bit data is 0 or 1 at different duty ratios. The transmission is completed by the characteristic ending signal, so that the one-way communication protocol between the host and each processing unit can be used for realizing one-to-many unit selection. The transmission channel of the existing hardware equipment is utilized, and the function of selecting the units of the bottom processing unit in one-to-many mode is achieved through the least occupation of hardware resources and the simplest implementation of an upper computer programming protocol.
The invention provides a single-wire communication method based on a CamerLink interface, which comprises the following steps:
s1, a transmission end is connected with a receiving end through a signal port, the transmission end controls the level of the signal port, and the receiving end detects the edge and the state of the signal port;
s2, starting transmission, wherein the signal port is at a low level and has a duration of T1;
s3, carrying out specific transformation on the level at the signal port, and detecting the high level duration Th and the low level duration Tl between two rising edges of the signal port by the receiving end, wherein if Th >2Tl indicates that 1 is received, and if 2Th < Tl indicates that 0 is received;
s4, the transmission is finished, the signal port is at a high level, and the duration time T2, T1> Tl and T2> Th.
As one embodiment, T1 is 1s, T2 is 1s, th=0.2s, t1=0.6 s when data 0 is transmitted. When data 1 is transmitted, th=0.6s, t1=0.2 s. When the signal fluctuation causes high-level and low-level duration errors and the system cannot judge whether the signal is 0 or 1, feedback retransmission information can be carried out regardless of the fluctuation part. The transmitting end may be an upper computer, and the receiving end may be an intermediate processing system. It should be further noted that other components are adopted to achieve the above effects, and should be within the scope of the present invention.
The invention provides a method for unidirectional limited data transmission by using a CameraLink idle control port. In the standard Camera link protocol, four pairs of differential output signals (acquisition card to Camera) are defined, namely Camera Control1 (CC 1), camera Control2 (CC 2), camera Control3 (CC 3), and Camera Control4 (CC 4). The camera manufacturer can define the signal to meet the requirement of the camera, the current general camera outputs frame synchronous signals (the early part of the camera also needs to latch signals) from the acquisition card through the four control signals, the signal direction is unidirectional transmission, and the physical layer technology such as low voltage differential is adopted, so the camera has stronger signal anti-interference capability and higher signal transmission bandwidth, the physical layer supports protocol transmission with higher baud rate, but the SDK at the top layer of the acquisition card is standard IO control on the interfaces of the four groups of signals, and the bus protocol with stricter time sequence requirements cannot be realized. The scheme uses the design of the 'start bit' in the asynchronous communication protocol, namely, the CC1 data line keeps high level in an idle state, and APP sets CC1 to low level through an IO control command and lasts for a specific time to represent the beginning of data transmission. The receiving party detects the edge and the state of the CC1 signal to obtain the information transmitted by the host, and starts the receiving process if the receiving party receives that the CC1 signal is 0 and lasts more than 0.75 seconds; the receiver detects that a high duration and a low duration are available between the two rising edges of CC1, indicating a 1 if Th >2Tl is received, and a 0 if 2Th < Tl is received.
Example 1
Transmission initiation: CC1 changes from 1 to 0 for Tl over 1 second;
transmission ends: CC1 changes from 0 to 1 for Th exceeding 1 second;
transmission data 0: CC1 high level time Th:0.2 seconds, CC1 low Tl:0.6 seconds (see fig. 2);
transmission data 1: CC1 high level time Th:0.6 seconds, CC1 low Tl:0.2 seconds (see fig. 2).
For example, one byte 00110101 is transmitted, i.e., the 0x35 device is selected, and the specific waveforms are shown in fig. 3 (this example is only for protocol representation). The invention can realize the one-to-many unit selection function of the bottom processing unit by using the transmission channel of the existing hardware equipment and the simplest upper computer programming protocol with the least hardware resource occupation based on the existing CameraLink technology. Or the protocol is extended to 16bit or 32bit, so that the complex communication such as address addressing can be performed. Because the transmission of each byte starts from the signal jump edge, the time precision requirement on the IO set command of the upper computer is not high, which is equivalent to the synchronization of each bit transmission.
The single line transmission method is used in cascade connection of CameraLink bus, and is used in unidirectional communication protocol between host and each processing unit to realize one-to-many unit selection.
Although embodiments of the present invention have been disclosed above, it is not limited to the details and embodiments shown and described, it is well suited to various fields of use for which the invention would be readily apparent to those skilled in the art, and accordingly, the invention is not limited to the specific details and illustrations shown and described herein, without departing from the general concepts defined in the claims and their equivalents.
Claims (5)
1. The single-wire communication method based on the CamerLink interface is characterized by comprising the following steps of:
s1, a transmission end is connected with a receiving end through a signal port, the transmission end controls the level of the signal port, and the receiving end detects the edge and the state of the signal port;
s2, starting transmission, wherein the signal port is at a low level and has a duration of T1;
s3, carrying out specific transformation on the level at the signal port, and detecting the high level duration Th and the low level duration Tl between two rising edges of the signal port by the receiving end, wherein if Th >2Tl indicates that 1 is received, and if 2Th < Tl indicates that 0 is received;
and S4, ending transmission, wherein the signal port is at a high level and has a duration of T2.
2. The single-wire communication method based on the camellink interface as set forth in claim 1, wherein: t1 is 1s.
3. The single-wire communication method based on the camellink interface as set forth in claim 1, wherein: and T2 is 1s.
4. The single-wire communication method based on the camellink interface as set forth in claim 1, wherein: when data 0 is transmitted, th=0.2s, t1=0.6s.
5. The single-wire communication method based on the camellink interface as set forth in claim 1, wherein: when data 1 is transmitted, th=0.6s, t1=0.2 s.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311093556.5A CN117194307A (en) | 2023-08-29 | 2023-08-29 | Single-wire communication method based on CamerLink interface |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202311093556.5A CN117194307A (en) | 2023-08-29 | 2023-08-29 | Single-wire communication method based on CamerLink interface |
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| CN117194307A true CN117194307A (en) | 2023-12-08 |
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| CN202311093556.5A Pending CN117194307A (en) | 2023-08-29 | 2023-08-29 | Single-wire communication method based on CamerLink interface |
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- 2023-08-29 CN CN202311093556.5A patent/CN117194307A/en active Pending
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