Gd32f4xx Ethernet chip (ENC28J60) driver migration

1、enc28j60 brief introduction

ENC28J60 Serial peripheral interface with industry standard （SPI） Independent Ethernet controller .
The main features ：
（1）SPI Maximum communication rate ：10Mb/s. Only support SPI The pattern of 0,0, And SPI Port requirements SCK Low level in idle state .
（2） Full duplex and half duplex modes are supported .
（3）8KB send out / Receive packet dual port RAM., Configurable sending / Receive buffer size .
（4）25MHz The clock .
（5） Working voltage 3.14v~3.45v.

ENC28J60 Download Chinese resources ：https://download.csdn.net/download/madao1234/85580753

2、enc28j60 Drive migration

enc28j60 Driver migration mainly involves ：GD32 MCU Of SPI Interface initialization 、 Replace enc28j60 In drive SPI Read write interface 、enc28j60 initialization .

2.1 GD32F4xx SPI Interface initialization

enc28j60 Of SPI Interface The highest speed is 10Mb/s, Only support SPI The pattern of 0,0. And ask for SCK Low level in idle state , Clock polarity selection is not supported . stay SCK Each rising edge of moves into the data , Commands and data pass through SI Pin in enc28j60. stay SCK Falling edge of from