Remora - ethernet NVEM / EC300 / EC500 cnc board

With Remora firmware now running on STM32 F4 and F1 series MCU's and ethernet communications working in a proof of concept using a w5500 interface. The next logical step is to develop native ethernet functionality.

There aren't many ethernet enable STM32 3D printer controller boards around but I came across the NVEM ethernet board for Mach3. It has an STM32F207 on board so expanding Remora to this board seems feasible.

I thought it would be fun to document my attempts to get Remora (with ethernet) up and running on this board. Also to give some hints on how I've tackled this on other boards.

This board also has opto isolated input and outputs and level shifting on the step and direction outputs. So a more "industrial" board suitable for normal CNC machines where a 3D printer controller board is not seen to be a suitable option.

 

The first step with any controller board is to get a simple "Hello World" up and running so that we have a working system configuration as a basis. Before diving into creating an MBed target, it's more straight forward to use STMCubeIDE initially. The NVEM board has no bootloader so no hassles with changing starting addresses.

[I took a back up of the original firmware before proceeding to upload any new code to the board]

The board has a 25MHz HSE crystal.

 

On the back of the board is the programming pads used in the factory. Some tracking of traces resulted in a usable ST-LINK interface.

 

For a "Hello World" it's easy if the board as an onboard LED that we can blink. Unfortunately no such luck with the NVEM board. A serial output will have to do. The board has two RS232 ports, one on the screw terminal and another on the other on the XH header.

These are true RS232 driven by a MAX3232 inverting transceiver giving protection to the STM32 UARTs, but this also means a RS232 to USB serial adaptor is needed rather than a TTL type that is used for direction connection to the MCU UART.

 

So after digging through the odds and ends, I found an RS232 adaptor from back when I was developing the Huanyang VSD component. First STMCube setup worked with data streaming out of UART2, the XH header.

 

I think MX_Master may have looked into this before, but it seemed how some of the pins were utilized didn't make much sense, so he didn't pursue it further.

Lets see how you go mate.