esp-idf/examples/ethernet/ethernet
suda-morris dc4c16f475 ethernet: add kconfig help for GPIO0 output mode
1. add kconfig help for GPIO0 output mode
2. fix a bug when select gpio0 output mode and initialize psram
3. make default config to official development board
4. fix wrong LAN8720 register index
2019-10-08 02:41:40 +00:00
..
main ethernet: add kconfig help for GPIO0 output mode 2019-10-08 02:41:40 +00:00
CMakeLists.txt cmake: make main a component again 2018-09-11 09:44:12 +08:00
Makefile Moved examples to new folders / categories. Removed example numbers from example names 2017-01-16 23:08:35 +01:00
README.md ethernet: add iperf example to test real bandwidth 2018-10-08 09:51:17 +08:00

Ethernet Example

(See the README.md file in the upper level 'examples' directory for more information about examples.)

Overview

This example demonstrates basic usage of Ethernet driver together with tcpip_adapter. The work flow of the example could be as follow:

  1. Initialises the Ethernet interface and enables it
  2. Send DHCP requests and tries to obtain a DHCP lease
  3. If successful then you will be able to ping the device

If you have a new Ethernet applicaion to go (for example, connect to IoT cloud via Ethernet), try this as a basic template, then add your own code.

How to use example

Hardware Required

To run this example, you should have one ESP32 dev board integrated with an Ethernet interface, or just connect your ESP32 core board to a breakout board which featured in RMII Etherent PHY. Currently esp-idf officially support only two Ethernet PHY: TLK110 from Texas Instruments and LAN8720 from microchip.

Configure the project

Enter make menuconfig if you are using GNU Make based build system or enter idf.py menuconfig if you' are using CMake based build system. Then go into Example Configuration menu.

  • Choose PHY device under Ethernet PHY option option

  • Set PHY address under PHY address option, this address depends on the hardware and the PHY configuration. Consult the documentation/datasheet for the PHY hardware you have.

    • Address 31 (default) for Espressif's Ethernet board with TLK110 PHY by default
    • Address 1 for the common Waveshare LAN8720 PHY breakout
    • Address 0 for other LAN8720 breakouts
  • Check whether or not to control PHY's power (if true, you need also to set PHY Power GPIO number later)

  • Set SMI MDC/MDIO GPIO number according to board schemetic, default these two GPIOs are set as below:

    Default Example GPIO RMII Signal Notes
    GPIO23 MDC Output to PHY
    GPIO18 MDIO Bidirectional
  • Select one kind of EMAC clock mode under EMAC clock mode option. Possible configurations of the clock are listed as below:

    Mode GPIO Pin Signal name Notes
    external GPIO0 EMAC_TX_CLK Input of 50MHz PHY clock
    internal GPIO16 EMAC_CLK_OUT Output of 50MHz APLL clock
    internal GPIO17 EMAC_CLK_180 Inverted output of 50MHz APLL clock (suitable for long clock trace)
    • The external reference clock of 50MHz must be supplied on GPIO0.
    • The ESP32 can generate a 50MHz clock using its APLL. When the APLL is already used as clock source for other purposes (most likely I²S), you have no choice but choose external clock.

Build and Flash

Enter make -j4 flash monitor if you are using GNU Make based build system or enter idf.py build flash monitor if you' are using CMake based build system.

(To exit the serial monitor, type Ctrl-].)

See the Getting Started Guide for full steps to configure and use ESP-IDF to build projects.

Example Output

I (0) cpu_start: App cpu up.
I (281) heap_init: Initializing. RAM available for dynamic allocation:
I (288) heap_init: At 3FFAE6E0 len 00001920 (6 KiB): DRAM
I (294) heap_init: At 3FFB4358 len 0002BCA8 (175 KiB): DRAM
I (300) heap_init: At 3FFE0440 len 00003BC0 (14 KiB): D/IRAM
I (307) heap_init: At 3FFE4350 len 0001BCB0 (111 KiB): D/IRAM
I (313) heap_init: At 4008966C len 00016994 (90 KiB): IRAM
I (319) cpu_start: Pro cpu start user code
I (113) cpu_start: Starting scheduler on PRO CPU.
I (0) cpu_start: Starting scheduler on APP CPU.
I (116) eth_example: Power On Ethernet PHY
I (126) system_api: Base MAC address is not set, read default base MAC address from BLK0 of EFUSE
I (126) emac: emac reset done
I (126) eth_example: Ethernet Started
I (2126) eth_example: Ethernet Link Up
I (11616) event: eth ip: 192.168.2.156, mask: 255.255.255.0, gw: 192.168.2.2
I (11616) eth_example: Ethernet Got IP Addr
I (11616) eth_example: ~~~~~~~~~~~
I (11616) eth_example: ETHIP:192.168.2.156
I (11626) eth_example: ETHMASK:255.255.255.0
I (11626) eth_example: ETHGW:192.168.2.2
I (11636) eth_example: ~~~~~~~~~~~

Troubleshooting

  • If the PHY address is incorrect then the EMAC will still be initialised, but all attempts to read/write configuration registers in the PHY's register will fail, for example, waiting for auto-negotiation done.

  • Check PHY Clock

    The ESP32's MAC and the External PHY device need a common 50MHz reference clock. This clock can either be provided externally by a crystal oscillator (e.g. crystal connected to the PHY or a seperate crystal oscillator) or internally by generating from EPS32's APLL. The signal integrity of this clock is strict, so it is highly recommended to add a 33Ω resistor in series to reduce ringing.

  • Check GPIO connections, the RMII PHY wiring is fixed which can not be changed through either IOMUX or GPIO Matrix. They're described as below:

    GPIO RMII Signal ESP32 EMAC Function
    GPIO21 TX_EN EMAC_TX_EN
    GPIO19 TX0 EMAC_TXD0
    GPIO22 TX1 EMAC_TXD1
    GPIO25 RX0 EMAC_RXD0
    GPIO26 RX1 EMAC_RXD1
    GPIO27 CRS_DV EMAC_RX_DRV
  • Check GPIO0

    GPIO0 is a strapping pin for entering UART flashing mode on reset, care must be taken when using this pin as EMAC_TX_CLK. If the clock output from the PHY is oscillating during reset, the ESP32 may randomly enter UART flashing mode. One solution is to use an additional GPIO as a "power pin", which either powers the PHY on/off or enables/disables the PHY's own oscillator. This prevents the clock signal from being active during a system reset. For this configuration to work, GPIO0 also needs a pullup resistor and the "power pin" GPIO will need a pullup/pulldown resistor - as appropriate in order to keep the PHY clock disabled when the ESP32 is in reset. See the example source code to see how the "power pin" GPIO can be managed in software. The example defaults to using GPIO17 for this function, but it can be overriden. On Espressif's Ethernet development board, GPIO17 is the power pin used to enable/disable the PHY oscillator.