ENC28J60 Ethernet chip driver for MicroPython v1.17 (RP2)
ENC28J60 is a popular and cheap module for DIY projects. At the moment, however, there is no driver for the MicroPython environment. The Python implementation seems easy for further improvements and self adaptation.
Copy enc28j60.py to your board into /enc28j60 directory.
Wiring requires pins for SPI: SCK, MISO, MOSI and ChipSelect and optionally Interrupt. Example wiring that uses SPI1 bus (any SPI bus can be used):
| ENC28J60 Module | RP2040 Board | Notes |
|---|---|---|
| VCC | 3V3 | requires up to 180 mA |
| GND | GND | |
| SCK | GP10 | SPI1 SCK |
| SI | GP11 | SPI1 MOSI/TX |
| SO | GP8 | SPI1 MISO/RX |
| CS | GP13 | SPI1 CSn |
| INT | GP15 | Optional |
- interrupt handler
Example of packet transmission to broadcast ethernet address:
from machine import Pin, SPI
from enc28j60 import enc28j60
spi1 = SPI(1, baudrate=10000000, sck=Pin(10), mosi=Pin(11), miso=Pin(8))
eth = enc28j60.ENC28J60(spi1, Pin(13))
eth.init()
srcMac = eth.getMacAddr()
tgtMac = bytearray([0xFF,0xFF,0xFF,0xFF,0xFF,0xFF])
payLoad = bytearray(64)
pktType = bytearray([(len(payLoad) >> 8) & 0xFF, len(payLoad) & 0xFF])
eth.SendPacket([tgtMac, srcMac, pktType, payLoad])Example of packet reception:
from machine import Pin, SPI
from enc28j60 import enc28j60
spi1 = SPI(1, baudrate=10000000, sck=Pin(10), mosi=Pin(11), miso=Pin(8))
eth = enc28j60.ENC28J60(spi1, Pin(13))
eth.init()
print("myMac:", ":".join("{:02x}".format(c) for c in eth.getMacAddr()))
print("ENC28J60 revision ID: 0x{:02x}".format(eth.GetRevId()))
rxBuf = bytearray(enc28j60.ENC28J60_ETH_RX_BUFFER_SIZE)
while eth.GetRxPacketCnt():
rxLen = eth.ReceivePacket(rxBuf)
print('rxLen:', rxLen, 'srcMac:', ":".join("{:02x}".format(c) for c in rxBuf[6:12]))Please refer to examples/Ntw.py file for details.
The file contains roughly written procedures for handling IP protocols in polling mode:
- IPv4 for not fragmented packets only, single static IP address
- ARP for IPv4 over Ethernet, simple ARP table
- ICMPv4: rx Echo Request and tx Echo Response
- UDPv4: rx and tx
- Simple UDP Echo server
MicroPython v1.17 for Raspberry Pi Pico does not include socket library. It also does not allow to run more than 2 threads at the time. It is hard to mimic network sockets in such environment. So polling mode seems reasonable solution.
from machine import Pin
from machine import SPI
import Ntw
if __name__ == '__main__':
# Create network
nicSpi = SPI(1, baudrate=10000000, sck=Pin(10), mosi=Pin(11), miso=Pin(8))
nicCsPin = Pin(13)
ntw = Ntw.Ntw(nicSpi, nicCsPin)
# Create UDP Echo server
udpecho = Ntw.Udp4EchoServer(ntw)
# Bind UDP Echo server to UDP port 7
ntw.registerUdp4Callback(7, udpecho)
# main loop
while True:
# Receive and process packets
ntw.rxAllPkt()