So I have two boards I’m working on. ONE is just becuase its 90% the same and i’ll be talking the most about in this post, the other card is because I need/want it for my laser etcher MCU upgrade. First off the board I’m hoping to upgrade my laser etcher with is an OLIMEXINO-STM32 . This board has an ARDUINO UNO footprint and is directly compatible with Arduino Uno hats sporting the STM32F103RBT6 with a 128kb flash. Much of this post currently is about the MACH3 USB CNC CARD BSMCE04U. It has more or less the same MCU the stm32f103rct6. The RCT6 has 256k flash. Everything below is covering the mach3 usb cnc card as of this posts date I have not yet received the OLIMEXINO in the mail yet.
These cards are plentiful and dirt cheap… So what I’m looking at is what is the best way to upgrade this card? I believe this card is a great candidate to be firmware upgraded with GRBL, MARLIN, Machinekit or maybe even SMOOTHIE, what do all of you think would be the best candidate for this card with the stock STM32 MCU? The controller chip the STM32F103RCT6 is pin compatible with a few different other chips. It could be swapped to an STM32F103RET6 which sports 512k flash and more ram. The current controller card has 256k flash. Now there are other chips like the GD32F103 which run at 108mhz over the 72mhz the STM run at. That could maybe be a nice upgrade as well? So I’m looking for guidance and advice on how to go about getting this card upgraded with better firmware. So far I have done some pin tracing, and found that the serial pins for upgrading the firmware are available.
If anyone is able to help I’d love to get GRBL? SUPERGRBL compiled for the STM32F103RCT6 and STM32F103RBT6 which are on the boards as is, and an Arduino bootloader as well so the card could be upgraded at any time further with out needing the serial setup. I know compiling grbl for this board will require some adjustments to I/O assignments to begin with. Now because of personal life issues I have at the moment, I have not had much time to dive into this project yet and give a full pinout post. I am also assuming that there are going to require some minor SMD mods with resistor(s) to deal with bootloader(s).
I may have made some errors but I dont believe so. The pins on the chip are very small, though I used a USB microscope when testing the pins. So far as I can tell the board construction is only a 2 layer top/bottom and the only bottom traces going from the stm32 chip to anything are to the idc header. All other traces are top side mounted. PIN 46 PA13 SWDIO, PIN 49 PA14 SWCLK. ON the chip its self the little circle is the pin 1 VDD/pin 64 VBATT location both are connected to the 3.3v regulator. THE BIG tab and the center small tab are both output from the ams1117 linear regulator. With this info that should be enough for anyone to start digging into this controller.
PLEASE SPARE ME THE HATE…. I built an input adapter for the 2×5 header when I tested the board with mach3 <– SUCKED BTW but the input is very signal sensitive I had to build one of these adapters https://www.cnczone.com/forums/contr…13028-cnc.html an other one of my posts. It cleaned up the signal wonderfully. I’ll post a photo of my PERF board when I get around to it.
There are 4 12/24v outputs, 4 12/24v inputs, PWM output and 4 motor step/dir signals built into the board. The IDC 2×5 header has +5v, grd, 6 GPIO’s, I have not DMM’ed the board to identify how the resistors are arranged yet? pull up/down-inline?? not sure.
The overall goal is to upgrade to the OLIMEXINO-STM32 "ARDUINO UNO footprint board" that I plan to put into this laser etcher that I’m building, LASER ETCHER . The uno works but its not great for high speed or raster images which is mainly what I’m going to be dealing with. Also the step rate suffers a shudder issue if the Arduino is overwhelmed.