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PIC18F4550 version |
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PIC18F4685 version |
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Schematic - note Vcc connection depends on usb-powered or self-powered application |
Development boards for microcontrollers are essential for debugging code and checking hardware peripherals before committing to the final build-configuration.My first microcontroller development board, which I called "MyDev1", has served me quite well; see 25th January. It is a typical, solderless, experimenting board; component leads are a push-fit into the holes. Its limitations, however, began to become apparent; noisy, intermittent connections, lack of flexibility and a real nightmare if I had ever attempted to use it with 40 or even 28 pin microcontrollers and interfacing with several hardware peripherals at once. Having unreliable connections is a really bad situation when the microcontroller is waiting, or looking, for changes.It was therefore time to upgrade to a better system; so I have produced "MyDev2". Now it is much easier to reconfigure for different peripherals, e.g. display, keypad, rotary encoder, comms ports, and to check their operation. Of course, I haven't omitted the LEDs, and "MyDev2" has many, ( different colours for different ports ), as it is always nice to see pretty lights as a visual indication of I/O port output state ! I could not avoid solderless connections entirely; but those are of a high reliability using good quality pin-headers.
"MyDev2" connects to the Microchip ICD2, ( In-Circuit Debugger No.2 ), for programming and debugging operations, thereby replacing my original home-made programmer, ( see 25th Jan, 8:06PM, purple box ).
Using a development board I was easily able to change between two mechanical rotary shaft encoders, ( control with knob ), from different manufacturers, choose the more appropriate one for my final application, and 'fine-tune' the PIC code to suit.
Incidentally, the microcontrollers featured in the pictures above are 40 pin Microchip parts, ( lower ) type PIC18F4685-E/P, and ( upper ) type PIC18F4550-I/P which incorporates a USB interface.
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