Absolute value encoder communication method and system based on spi

Abstract

The invention discloses a spi-based absolute value encoder communication method and system. An encoder sequentially receives clock signals sent by an SPI interface of an MCU host; starting to encode the data to be transmitted according to the rising edge or the falling edge of each clock signal, and framing the encoded data in a manner that eight bytes form a group to collect a plurality of data frames; according to the method, each byte in each data frame is sequentially sent to an MCU host according to a sequence until to-be-transmitted data is sent completely, data sending and receiving are carried out by using 8-bit and 16-bit data formats of SPI interface standards of a common MCU, and the data are synchronously transmitted according to bytes instead of traditional bit-by-bit transmission. Therefore, data verification and accurate transmission can be realized under the condition that special hardware is not used, the data transmission rate and the data transmission reliability are improved, and the complexity and the use cost of a hardware system are reduced.

Description

technical field [0001] The invention relates to the field of absolute encoder communication, in particular to an SPI-based absolute encoder communication method and system. Background technique [0002] The current absolute encoder communication protocols include ssi, biss-c, EnDat, Tamagawa protocol, etc. Most of these communication protocols use the RS-422 or RS-485 standard as the physical layer, and use the synchronous serial transmission method to transmit one-way or two-way data. The frame is generally composed of bit streams, and time is used as the frame interval. At present, most encoders use synchronous transmission technology for high-speed communication, and rarely use asynchronous transmission technology. The main reason is that asynchronous transmission requires a high-precision clock system under various environmental conditions. The above protocols either have no error checking, or use a bit stream to transfer data. And the encoders using these protocols ar...

AI Technical Summary

Problems solved by technology

The above protocols either have no error checking, or use a bit stream to transfer data

And the encoders using these protocols are basically realized by application-specific integrated circuits, or by CPLD or FPGA. However, if application-specific integrated circuits or CPLD or FPGA are used, the transmission time of the equipment is very fast, and the data cannot be error-checked and the cost is high. Higher, if the commonly used single-chip MCU is used, because it only has synchronous serial or asynchronous serial interface (SPI, USART), these interfaces generally only support data transmission of no more than 16 bits, it is difficult to accurately send or Therefore, it is necessary to design a new transmission control protocol that can realize communication between the microcontroller and the encoder

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