Marc's open source hardware activities
Every LPC-base PCB I build so far is programmed using the UART-ISP-protocol. As I'm biased toward mains voltage applications like motor inverters and high power switch mode power supplies, I need a galvanic insulation between the microcontroller/power stage and the PC used for programming. GIM3b does exactly that: It provides 3.3V level UART plus /RESET and /BOOT signals and provides over 500V potential difference between USB levels and microcontroller GND.
Have a look at GIM3b schematic and GIM3b board
Connectors are USB-Mini-B and MicroMatch-6 (1.27mm ribbon cable pitch, 6-way).
If you really need one, please contact me. I would sell for 30EUR or so.
Invcore1 schematic and InvCore1 board
Invcore1 is a LPC213x based board that serves as controlling unit for many projects. Invcore1 is designed using halogen-free, lead-free and beryllium-free components besides being RoHS-compliant. All (1.27mm pitch) ribbon cable connectors are MicroMatch (or MiniModule from Wuerth Electronics). Power supply is a WAGO-2060-2 clamp. Interfaces:
Invcore1 is lacking a true double-edge-controlled 3-phase (or even 2-phase) PWM.This can be achieved with a LPC176x device. It turns out that most applications I wanted to implement do not need that. The LPC2100 family is easy to use - less clocking complexity, not that much power-saving possibilities, lower pin-count. And: I do like the 32-bit ARM instruction set for assembly language!
- 4 Sensor inputs with up-to 2 ADC inputs each.
- 3 I²C connectors on one I²C bus, 2 connectors: 4pins, 1 connector 6 pins (I²C + /RESET and /INT for PCA9555 as an example).
- one 8-pin connector for EA-DOGM128 style displays.
- one 8-pin connector for 2 rotary encoder inputs (digital potentiometer) and 2 pushbuttons.
- 3 connectors for 3 single edge controlled PWMs + enable, suitable for devices like IRF2184 or LM5104 or similar.
- 2 connectors for restricted 2 double edge controlled PWMs for devices like IR2214/2214.
- one power supply 10V to 15V: driving voltage for MOSFETs / IGBTs and power supply for the uC and analog circuitry. Switch mode step down 3.3V integrated (LM5009).
- Piezo buzzer driven by amplifier tied to AOUT (DAC-output, software volume control, sound mixing ;-)
If you have a closer look at the LPC213x pin-out and the LPC175x/176x pin-out you will notice, that LPC213x has a much heavier focus on ADCs than LPC17 - which is important for the applications I have in mind. So I believe, LPC213x is the better choice for all but 3-phase applications well above 600V bus voltage.
I'm working with the LPC families LPC21xx, LPC23xx, LPC175x, LPC176x, LPC11xx, LPC81x - my decision is not based on the habit to use a specific core, really.
Invcore1 is augmented by the following connectable components:
- UI-I2C-B8-L8: a PCA9555A-based 8 pushbutton, 8 LED user interface board.
- IO-INPUT-DP2: 2 rotary encoders (digital potentiometer) + 2 pushbuttons. THE user input board.
- DOGL-128: a EA-DOGM128 / EA-DOGL128 board for 128x64 pixels monochrome graphic output.
- ICIO-I-HALL-1A: a +-50A to +-200A Hall-sensor current sensor for measuring output current; galvanic isolation.
- ICIO-I-Shunt: a 0..+20A GND-based current sensor for measuring unipolar output current.
- 1 to 3 LM5104-Bridge-V2: LM5104-based phase leg, MOSFETs: IRFS3206, 100A / 60V / 10A continuous without cooling.
- 1 to 3 IR2184-V2: IR2184-based phase leg, IGBs: TSTWG30NC60WD, 30A / 600V / 30A continuous.
Most components were designed in 2013, software development started in 2013.
The primary goal was Zn-plating of steel parts and plasma-electrolytic oxidation. However, software development soon targeted on re-usable modules for all kinds of applications mentioned below and proper user-interface design was soon recognized essential to the stand-alone usability of the system.
This set of PCBs paired with the cool software I created represent the building blocks of many interesting applications:
- 3-phase motor inverter
- Magnetic pulse generator
- Induction heating
- Spinning rod magnets at up-to 600 rev/second just for the fun of it!
- High voltage constant current sources: arcs!
- Low power dissipation electrolysis current source.
- Lots of other fun stuff.
Last edit: 2013-11-08.