Bus Pirate Demo Board v5 design overview
[Available for $xx.xx at Seeed Studio].
Bus Pirate Demo Board v5 is a multiple protocol, multiple IC emulator. To test out major functions of the Bus Pirate we programmed one microcontroller to emulate various different devices you could connect to the Bus Pirate. By selecting different combinations of jumpers you are in fact changing the function and the interface protocol of the board. It can emulate the following functions:
- PWM generator
- ADC converter
- DAC converter
- SRAM memory
Communicating with the Bus pirate over the following protocols:
- TBD (to be decided)
History and related links
The Demo Board v5 uses a small 8bit PIC16F1829 microcontroller (U1) that is powered directly from the Bus Pirate IO header. The power pin (VDD) is decoupled with a 0.1uF capacitor (C1).
The ICSP programing connection is brought to a header for easy development. The MCLR (RESET) programming pin is connected to the power supply through a diode (D1) and 10K pull-up resistor (part of the RN2 resistor array). The diode stops the 9volt supply using during programming from damaging the rest of the circuit.
Two LEDs (LED1 and LED2) are connected to pins 5 and 7 of the microcontroller through current limiting 1k resistors (R1 and R2).
Also added on the MCLR programing pin is the current limiting resistor R3 and voltage limiting 9V zener diode (D2), making it compatible with programmers that can only supply 13V programming voltage. To enable this mode you simply need to cut away the trace below R3 and populate both R3 and D2. If you don't need this just leave the trace connected, and don't populate the relevant components.
The table below demonstrates how the protocol is set. 0 indicates that the jumper is not present, 1 indicates that it is present. So for example 01 means that the left jumper should be taken off, while the right jumper needs to stay on.
The table below demonstrates how to set the device you want to emulate. '0' indicates that the jumper is not present, '1' indicates that it is present. So for example '01' means that the left jumper should be taken off, while the right jumper needs to stay on.
Analog input front end contains a voltage divider (RN2) which is connected to pins 3,9, and 10 of the microcontroller, corresponding to channels 0,1,and 2 of the internal ADC.
Warning: Never connect a signal with a voltage higher then the Demo Boards Power supply.
DAC Buffer circuit
The DAC output of the microcontroller is buffered with a LMV321 op amp (IC1) in a buffer amplifier setup. It has a 0.1uF decoupling capacitor (C4) and two 1uF stabilizing capacitors (C2 and C3) on it's input and output.
Bus Pirate header
- PCB and placement notes
- soldering advise
Click for a full size placement image.
- Operating modes
- extra software required
Taking it further
Here's some ideas for the future:
We'll post the most recent firmware updates on our blog. You can also join the discussion in the [forum].
You can [get one for $00], including worldwide shipping.
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