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A sending method and descriptor technology, applied in the field of communication, can solve problems such as slow speed, difficult expansion, and consumption of system resources, and achieve the effects of length optimization, improved transmission and processing capabilities, and guaranteed determinism and real-time performance
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AI technical title is built by PatSnap AI team. It summarizes the technical point description of the patent document.
A sending method and descriptor technology, applied in the field of communication, can solve problems such as slow speed, difficult expansion, and consumption of system resources, and achieve the effects of length optimization, improved transmission and processing capabilities, and guaranteed determinism and real-time performance
CN102420763BActive 📅 Publication Date: 2014-05-07CHINESE AERONAUTICAL RADIO ELECTRONICS RES INST
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[0029] The preferred embodiments of the present invention are given below in conjunction with the accompanying drawings to illustrate the technical solutions of the present invention in detail.
[0030] To achieve deterministic, real-time, and reliable transmission of large-capacity data in the AS5643 network, such as figure 1 As shown, according to the data flow sequence of the data packets from the application layer, the transaction layer, the link layer to the physical layer, the DMA transceiver is improved and optimized from top to bottom. The following methods are applicable to both CC nodes and REMOTE nodes.
[0031] 1. Application layer packet length optimization includes the following:
[0032] In order to reduce the packet loss rate and increase the bandwidth utilization rate, the present invention optimizes the data packet length from the application layer of the sending node. The frame format of the AS5643 protocol is as follows figure 2 As shown, assuming that ...
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Abstract
The invention discloses a direct memory access (DMA) sending method, which comprises the following steps of: 301, according to an application layer, determining the length and number of data packets which are sent in each period; 302, creating a descriptor for each data packet; 303, judging whether the descriptor is the first descriptor; 304, regarding the current descriptors as the head and tail of a new descriptor queue; 305, resetting a RUN bit in a context control register; 306, according to an active bit in the context control register, checking a result of the step 305; 307, writing the addresses of the descriptors into a link layer command pointer register; 308, setting the RUN bit in the context control register as 1; 309, judging whether sending of N data packets is finished; 310, reserving DMA sending descriptors in a centralized mode; and 311 to 314. By adoption of the DMA sending method, a plurality of data packets can be continuously sent, and transmission of high-capacity data is realized.
Description
technical field [0001] The present invention relates to a communication technology, in particular to a DMA (Direct Memory Access, direct memory access) sending method. Background technique [0002] With the continuous upgrading of avionics system architecture and the rapid development of computer technology, the processing capacity of single-board computers has been greatly improved. The communication bottleneck of the system will no longer be the processing module, but the data between modules and between systems and between systems. communication bandwidth. Avionics bus technology is getting more and more attention. Some high-speed serial buses such as IEEE 1394B are gradually being applied to the design of advanced avionics systems. It has significant advantages such as high speed (up to 3.2Gbps), hot plugging, point-to-point transmission, easy expansion, and long transmission distance. [0003] According to the application in the field of military and air traffic, on t...
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