With an STM32 board with Ethernet compatibility, this library allows a STM32 board (NUCLEO, DISCOVERY, ...) to connect to the internet.
This library follows the Ethernet API from Arduino.
For more information about it please visit: http://www.arduino.cc/en/Reference/Ethernet
This library is based on LwIP, a Lightweight TCP/IP stack, available here:
http://git.savannah.gnu.org/cgit/lwip.git
The LwIP has been ported as Arduino library and is available thanks Arduino Library Manager.
Source: https://github.com/stm32duino/LwIP
The LwIP has several user defined options, which is specified from within the lwipopts.h file.
This library provides a default user defined options file named lwipopts_default.h.
User can provide his own defined options at sketch level by adding his configuration in a file named STM32lwipopts.h or
extend the default one by adding some extra configuration in a file named lwipopts_extra.h.
There are alternative inits of the Ethernetinterface with following orders:
Ethernet.begin();
Ethernet.begin(ip);
Ethernet.begin(ip, subnet);
Ethernet.begin(ip, subnet, gateway);
Ethernet.begin(ip, subnet, gateway, dns);
This is more logical. A MAC address is no more needed and will retrieved internally by the mbed MAC address!
You can get the MAC address with following function, this must done after Ethernet.Begin()
uint8_t *mac;
Ethernet.begin();
mac = Ethernet.MACAddress();
You can also set a new user based MAC address, this must done before Ethernet.begin()
uint8_t newMAC[] = {0x00, 0x80, 0xE1, 0x01, 0x01, 0x01};
Ethernet.MACAddress(newMAC);
Ethernet.begin();
EthernetClass::maintain() in no more required to renew IP address from DHCP.
It is done automatically by the LwIP stack in a background task.
An Idle task is required by the LwIP stack to handle timer and data reception.
This idle task is called inside a timer callback each 1 ms by the
function stm32_eth_scheduler().
A DEFAULT_ETHERNET_TIMER is set in the library to TIM14.
DEFAULT_ETHERNET_TIMER can be redefined in the core variant.
Be careful to not lock the system in a function which disabling IRQ.
Call Ethernet::schedule() performs an update of the LwIP stack.
You can find information at https://github.com/stm32duino/Arduino_Core_STM32/wiki/STM32Ethernet