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Hot Chips - PIC16F676

scottiebabe

For the upcoming  7-segment project14 event, I wanted to use an relatively old 8bit microcontroller that is compatible with my Pic Kit1. The PIC16F676 was one of 2 sample MCUs that shipped with the kit.

I am amazed, given component shortages, I was even able to purchase a PIC16F676 Smiley

I got a real smokin deal at $3.40 /UNIT

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The PIC16F676 is feature packed!

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A whopping 64 bytes of RAM.

The flash program memory is 14-bits wide, so 1024 words is 1792 bytes.

Cost per MB = $3.4 / ( 1792 / 2^20) = $1989.48 / MB

Of course you get a processor, sram, eeprom, adc, timer, etc as well, so its not an accurate cost figure. 

  • The pickit1 came with a treasure trove of application notes, sample programs, and tip's and tricks for working with low pin count MCUs. One of the tricks is LED multiplexing across gpio pins. For example on the pickit1 to light up only LED D0 one would:

    image

    As recommended in the starter guide:

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    Blinky 2.0:

    Of course you can use any of the newer pic icsp tools, but that wouldn't have the same nostalgia factor for a simple 7-segment display project.

  • in reply to scottiebabe

    Also commonly referred to as 'Charlieplexing' or 'tristate multiplexing'. 

  • in reply to beacon_dave

    Thanks for the technical term Smiley, I'm not sure if I have every used the technique for LEDs myself. 

    Of course it didn't work the first time because the TRISA register is in Bank1... bank switching good memories LOL