MCU PCB
To make debugging easier we separated the functionality of the printer into 2 printed circuit boards. They are mated with right-angle headers. The MCU PCB is shown below. This mainly broke out the ports to control each motor. In addition, it has the flash chip, USB, and JTAG debugger all mounted on board. When designing this board, it became paramount to put silkscreen labels everywhere. This reduces errors when populations the board and helps debug. Furthermore, it is important to follow the MCU datasheet exactly. We had to do a respin because of a misrouted power pin. JTAG debugging is fairly easy to implement as long as the datasheet is followed exactly.
MCU PCB
JTAG Circuitry
MCU Circuitry
Power, Motors, and Heaters PCB
3D Rendering of the Power, Motors, and Heaters PCB
This PCB includes circuitry that powers the motors, heaters, microcontrollers, fans, and switches. The CTL pins on the right side of the board are the right angle headers that connect to the MCU board described above. Due to the number of connections needed to control each motor, a set of 4x2 header pins for each motor are also connected to the MCU board.
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At the bottom of the page are images of the schematic used for this board.
Motor Driver PCB V2
To help aid development of motor control and to gain a better idea of how to layout and implement the TI DRV8886 Stepper Motor Driver IC, breakout boards for these IC's were created. Two revisions of this PCB were created after errors were found on the first revision and familiarity with Altium was gained. The schematic of the second version were implemented on the final board.
