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Counting needed pins on MCU

A project log for Fiber optic Power/Link tester

One tester for determination optical signal speed, wavelength and power.

AleksejsAleksejs 04/23/2018 at 09:390 Comments

It's time to count all pins to select MCU.

For every SFP DDM needed 3 pins, summary it's 9 pins. 

InGaAs photodiode needs 2 pins, summary 4 pins. 

Laser diode driver needs 1 pin. 

Two Opto-Mechanical switch needs 8 pins each.

Control buttons - 4 pins. 

Display spi - 5 pins. 

So summary I need from MCU minimum 40 pins.

For making economy on MCU pinnouts, I think to use multiplexors for SFP and for switches. 

Working now on mux selection... 

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