SPI Multiplex Chip Reduces Control Lines and Interference
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Solution Overview
Problem
Existing RF circuit board systems face challenges with SPI control, including increased complexity and interference due to the need for multiple control lines, limited flexibility in supporting different SPI masters and data widths, and data corruption issues caused by long trace lengths and heavy serial loads.
Innovation Solution
The proposed solution involves an SPI multiplex chip that minimizes SPI line control from the SPI master to SPI slave devices, supports multiple types of SPI masters with different serial data widths, and provides flexibility in RF design by using field programmable gate arrays or complex programmable logic devices.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the number of SPI slave devices is increased, then the functionality of the RF system is improved, but the number of SPI bus and control lines increases proportionally, making PCB routing difficult
Solution Approach 1:
The patent combines multiple SPI control lines into a single shared control line by implementing an SPI bus arbiter that manages access from multiple slave devices to the master device through time-division multiplexing, thereby reducing the number of control lines required on the PCB
Solution Approach 2:
The patent introduces an SPI bus arbiter as an intermediary device between the SPI master and multiple slave devices, which coordinates and manages the communication between them, allowing multiple slaves to share a single control line while maintaining proper signal integrity
2Ease of operation
If the SPI bus trace is routed over a long distance, then the connection flexibility is improved, but the reflection in the transmission line causes undershooting and/or overshooting in data transition
Solution Approach 1:
The patent applies preliminary action by implementing proper termination resistors and impedance matching at the beginning of the SPI bus trace routing, which prevents reflection issues before they can affect data transitions, allowing long-distance routing without compromising signal integrity
3Adaptability or versatility
If multiple SPI master devices are used to support different data lengths, then the compatibility with various SPI slave devices is improved, but the number of SPI master devices increases
Solution Approach 1:
The patent implements universality by designing a single SPI master device with configurable data width capabilities that can adapt to different SPI slave devices regardless of their data length requirements, eliminating the need for multiple specialized master devices through software or hardware configuration
4Adaptability or versatility
If GPIO pins are used for device chip selection, then the flexibility in device selection is improved, but the number of GPIO pins required increases
Solution Approach 1:
The patent applies segmentation by dividing the chip selection function into multiple bits that can be combined to address multiple slave devices, allowing a limited number of GPIO pins to control a larger number of devices through binary encoding of the chip select signals
Data Source
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AI summary
A method and system are provided herein for serial peripheral interface (SPI) control. The method may first include setting a general purpose input/output (GPIO) register to select an SPI data bus from at least one of an SPI master. The method may proceed to setting the SPI master to send a first data set of SPI serial data. The first data set may be provided to an SPI slave device. A second data set may be retrieved from the SPI slave device.