常见的Quad-SPI引脚含义

灰太狼 2022-10-09 02:53 438阅读 0赞

常见的SPI接口设备通常有：Single-SPI (traditional SPI), Dual-SPI, Quad-SPI, Dual-quad-SPI（Device connects two Quad I/O SPI devices with a single CS\# resulting in an eight bit I/O data path. This Byte I/O interface is called Dual-Quad I/O. ） and Octo-SPI，而且多数据引脚通常支持低数据引脚协议配置；  
![Quad-SPI FRAM][]

*  **VCC** \- this is the power pin. Since the chip uses 3-5VDC you should pick whatever the logic voltage you’re using.For most Arduino’s that’s 5V.
 *  **GND** \- common ground for power and logic
 *  **HOLD** \- this is a ‘wait’ pin for the SPI bus. When pulled low, it puts the SPI bus on hold. This is different than the CS pin because it doesnt stop the current transaction. Its good if you want to talk to other SPI devices and streamdata back and forth without stopping and starting transactions.
 *  **SCK** \- This is the SPI clock pin, its an input to the chip
 *  **MISO** \- this is the Microcontroller In Serial Out pin, for data sent from the `FRAM` to your processor
 *  **MOSI** \- this is the Microcontroller Out Serial In pin, for data sent from your processor to the `FRAM`
 *  **CS** \- this is the chip select pin, drop it low to start an SPI transaction. Its an input to the chip
 *  **WP** \- Write Protect pin. This is used to write protect the status register only! This pin does not directly affect writeprotection for the entire chip. Instead, it protects the block-protect register which is configured however you want(sometimes only half the `FRAM` is protected)

> FRAM is ‘ferroelectric’ RAM,which has some very interesting and useful properties. Unlike SRAM, FRAM does not lose the data when power is lost.In that sense it’s a durable storage memory chip like Flash. However, it is much faster than Flash - and you don’t haveto deal with writing or erasing pages.This particular FRAM chip has 64 Kbits (8 KBytes) of storage, interfaces using SPI, and can run at up to 20MHz SPIrates. Each byte can be read and written instantaneously (like SRAM) but will keep the memory for 95 years at room© Adafruit Industrieshttps://learn.adafruit.com/adafruit-spi-fram-breakoutPage 3 of 20.

也有使用8pin数据的spi协议存储芯片，例如驰拓科技的这款MRAM存储芯片；  
![Octo-SPI MRAM][]

## 参考文章 ##

1.  [Octo-SPI interface on STM32 microcontrollers][]
2.  [Adafruit SPI FRAM Breakouts][]

[Quad-SPI FRAM]: /images/20221005/7e3ee4d839cd43cdb2fbec887f5381f5.png
[Octo-SPI MRAM]: /images/20221005/ba5be9e37b1040548d314b05d968acda.png
[Octo-SPI interface on STM32 microcontrollers]: https://www.st.com/resource/en/application_note/dm00407776-octospi-interface-on-stm32-microcontrollers-stmicroelectronics.pdf
[Adafruit SPI FRAM Breakouts]: https://www.mouser.cn/datasheet/2/737/adafruit_spi_fram_breakout-1900787.pdf