DMA-based method for automatically defining ending of variable-length frame in communication among SPI devices

Abstract

The invention discloses a DMA-based method for automatically defining ending of a variable-length frame in communication among SPI devices. A branch signal is led out from a chip selection output signal in the master device and is connected to a chip selection level value change monitoring interface in the slave device. When one frame of message of the master device is sent completely, both the level value of a chip selection output signal in the master device and the level value of a branch signal of the chip selection output signal are changed. And the slave device detects the change of thelevel value through the chip selection level value change monitoring interface to judge the end of the primary communication, defines that the sending of a frame of message of the master device is ended, and then performs subsequent message receiving processing and DMA attribute configuration of the slave device for the next communication. In the SPI communication adopting the DMA mode, the SPI master device can flexibly send the message frame with the variable length, and the slave device can accurately and automatically define the frame tail of one frame of variable-length frame message of the master device.

Description

Technical field: [0001] The invention relates to a method for automatically defining the end of a variable-length frame in communication between SPI devices based on DMA. Background technique: [0002] With the development of semiconductor and integrated circuit technology, chip devices with various forms and rich functions have entered all aspects of life and industrial applications, and the information interaction between chips has become a key part of system operation. An interface for communication, because of its simple physical interface, fast transmission speed, and stable transmission quality, it is widely integrated in the communication interface module of chip equipment. [0003] There are three main ways to implement SPI communication: direct unbuffered communication, FIFO buffered communication, and DMA communication. Among them, the first type of direct unbuffered communication, each communication can only realize data transmission with a length of up to 4 byte...

AI Technical Summary

Problems solved by technology

[0005] The above-mentioned method 1 is relatively common, but the existing problems are also obvious. First, the receiver needs to be able to respond quickly, handle the interrupt within one byte, and complete the DMA setting, which has a high impact on the processing performance of the receiving device. Second, error accumulation may occur. Since the first byte is required to set the DMA, the communication quality needs to be very reliable. Otherwise, when the communication process is disturbed, the length of the first byte is set incorrectly, which will cause DMA. The receiving error is wrong, and the subsequent processing of DMA must meet the initial setting to trigger, resulting in the accumulation of unrecoverable continuous communication errors; method 2 has certain special requirements, that is, the chip device needs to have a special idle interrupt function, and this function Not all chip devices are shared, and do not have general versatility

Images