VDDCORE/VCAP setting

Nigel Goodwin

Super Moderator

Most Helpful Member

• Jul 4, 2023

• #2

Page 23 of the datasheet shows the minimum connections, and page 25 clearly says you MUST use a suitable capacitor if you're using the internal regulator (and suggests a suitable component). ENVREG is explained on page 43 - linked to Vdd to enable the internal regulator - on devices which include ENVREG. Page 243 explains what happens if it doesn't have it, with F type devices requiring the special 10uF.

As I see it you just need the 10uF for your F series component.

Any particular reason you're using this chip?, are you looking for a cheap device for large scale production?.

 

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Peet19

Member

• Jul 4, 2023

• #3

Thanks. There is no ENVREG pin on this. So how do I enable it now? I put a 10uF capacitor on the VDDCORE pin, but I don't know where to enable it. Or is that enough?Yes, it's a pretty cheap PIC and I'm planning a programmable thermostat with an LCD display. I even thought about the 18F24K20 or the K22, but you can't get them very often. I think Microchip stopped production of the K20.Now how do I enable the voltage regulator?

 

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rjenkinsgb

Well-Known Member

Most Helpful Member

• Jul 4, 2023

• #4

On the types we use that need a VCAP capacitor, we use a 10uF surface mount ceramic close in to the MCU.

 

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T

tumbleweed

Well-Known Member

Most Helpful Member

• Jul 4, 2023

• #5

On the 18F there is no ENVREG pin, just connect a 10uF to VDDCORE.
There's nothing else you must do. When you apply VDD you should measure 2.5V at the VDDCORE pin.

The 18LF do not have the regulator and you have to supply VDDCORE externally.

 

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Solution

Peet19

Member

• Jul 5, 2023

• #6

I understand, thank you so mutch.

 

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Peet19

Member

• Jul 5, 2023

• #7

One more quick question.
I don't understand the output current of the ports exactly.
Can PORTA, D, E only give 4mA output current?

 

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T

tumbleweed

Well-Known Member

Most Helpful Member

• Jul 5, 2023

• #8

Can PORTA, D, E only give 4mA output current?

Click to expand...

That's the spec on the 25J10. Many of the 'J' family are like this.

 

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Peet19

Member

• Jul 5, 2023

• #9

Oh, that's not good. Thanks.

 

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T

tumbleweed

Well-Known Member

Most Helpful Member

• Jul 5, 2023

• #10

The Q family is pretty nice and can run at lower VDD without requiring a VDDCORE/VCAP, something like an 18F25Q10, although I know getting parts is still a problem...

 

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Peet19

Member

• Jul 6, 2023

• #11

I undestand, thanks.

 

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