FT232 Schematic Question

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I'm looking to add the FT232RL chip to a PCB for my ATmega running at 5V.

I came across this schematic at  http://electronics-diy.com/FT232RL_USB_to_Serial_Adapter_for_PIC_AVR_ATMEGA_ARDUINO_MCUs.php

Most everything they did makes sense to me.

 

QUESTION:

Why are they connecting VCC to the 3.3V out pin???  And even more confusing, why are they tying 3.3 out directly to ground??  I can understand having a cap between VCC and ground.  What they are doing off pin 17 is baffling me here.  What am I missing?

 

Thanks in advance!!

 

I don't claim to have a clue what I am doing

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MechE74 wrote:
Why are they connecting VCC to the 3.3V out pin???  And even more confusing, why are they tying 3.3 out directly to ground??  I can understand having a cap between VCC and ground.  What they are doing off pin 17 is baffling me here.  What am I missing?

Pin 17 VCC3 crosses but does not connect to VCCIO/VCC5 (pins 4/20), but does connect to a bypass cap 100nf.

The datasheet for ft232 should explain each pin and how it should be used, do you have the DS?

Jim

Perhaps this schematic is better: https://cdn.sparkfun.com/datashe...

Edit added schematic link

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Last Edited: Thu. Feb 13, 2020 - 01:49 PM
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ki0bk wrote:

 

Pin 17 VCC3 crosses but does not connect to VCCIO/VCC5 (pins 4/20), but does connect to a bypass cap 100nf.

The datasheet for ft232 should explain each pin and how it should be used, do you have the DS?

Jim

 

 

Thanks for the reply Jim.  Yes I have the datasheet.   

The light bulb just went on. 

I'm going to chock this up to it being first thing in the morning... 

The two caps tie to a common ground node.  The way he chose to draw it kind of threw me off.

 

Time for more coffee.

 

Ever asked something that was so basic you wish you could just take it back? LOLcoollaugh

 

 

 

 

 

 

I don't claim to have a clue what I am doing

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MechE74 wrote:
Ever asked something that was so basic you wish you could just take it back?

More times then I care to remember, enjoy the caffeine

 

Jim

 

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