[sdiy] Microchip PIC 5 x 4 matrix

[Jean-Pierre Desrochers]

Nice I2C interface chip Rick.

The tradeoff I face here is always the same..
More PIC code with less IC's or
Less PIC code with more IC's..

JP


<
Le 2015-10-07 11:21, Rick Jansen a écrit :
> If you can use an I2C bus the PCF8574 is nice for this too. 2 pins for
> serial communication, plus an interrupt, if you want to use that. With
> 3 8574's you can read 24 switches. Each switch just connects to GND,
> no matrix necessary.
> 
> rick
> 
>> On 07 Oct 2015, at 15:52, Jean-Pierre Desrochers <jpdesroc at oricom.ca> 
>> wrote:
>> 
>> I'm about to build a MIDI foot controller
>> using around 20 normally open footswitches
>> with there respective state LEDs.
>> I have a bunch of PIC16F88 micros and want
>> to use one for this project using as less pins as possible.
>> (9 pins for the matrix)
>> I figured out a way to read and feed all switches
>> and LEDs this way:
>> 
>> http://www.arcenson.com/public/PIC16F88_5x4_matrix.JPG
>> 
>> All the switches and LEDs will be processed one after each other
>> in an endless loop..
>> RB5 will send the MIDI data.
>> 
>> Does anybody see something I forgot in that drawing ?
>> I'm not home and will try it tonight.
>> 
>> Thanks. JP
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