Hello everyone,
after my more or less failed lpc1768 3d controller board ("https://reprap.org/forum/read.php?159,876626") which doesn't wanted to work, but after a long time I found out why: I needed to keep the bootloader entry pin high during the entire flashing instead of pushing the button and releasing it. But this board is now declared dead by me and no further development will be made because: 1. Chips shortage makes it hard to find certain chips and parts. 2. RepRapFirmware will stop supporting the lpc1768.
But I decided to make an other board, more modular. It ist more of a line or system of boards. The MCU is on its seperate daughterboard, so upgrading or custom boards for specific or boards with support for stepperdriver in stepstick format found on the PrntrBoardV2 (or boards with integrated stepper driver or just boards with screw terminals an optocoupler for big external stepper driver are also posible).
The board found in my github is more of a concept, an example. It shows a version for four stepper and three mosfets found in a normal 3d printer. The connector for the daughterboard has the folowing system: the first 2x2 pins are for power. The daughterboard get from motherboard VDD, 5V and ground. 3.3V will be generated by the daughterboard, if it is needed by the daughterboard. The daughterboard itself provide the logiclevel power back to the motherboard (normaly 5V or 3.3V). The next 2x2 pins are SPI. The next 3x2 pins are endstops. And at last there are groups of 3x2 pins for the stepperdriver and mosfets. These pins are stepperdriver movment signals, a signal pin for the mosfet and two pins for the serial connection, where one pin also is the chip select for spi, if the stepper driver use spi instead of serial. This can go up to 6 steppers/mosfets, which means, this connector would go up to 50 pins. Above this a second connector is needed or ribbon cables (because the connector would be really big), but that is not final.
Currently I'm thinking of adding i2c. And another idea would be to make a separet pin for the chip select combined with an extra pin for a thermistor, so that for each stepper/mosfet/thermistor are 4x2 pins.
What are your opinions?
