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Loren77

Beginner

Date of registration: Nov 12th 2017

Posts: 2

1

Tuesday, November 14th 2017, 4:30pm

[SOLVED] J-Link Vcc Connect Question

Greetings!

Quick question about the Vcc (Vref) Pin on the J-Link connector.

1. I believe this is actually an input used to set the SWxx pins' signal level. Do I understand this orrectly?

2. Do I need to provide a reference voltage or is there a way to manually set the Vref in the J-Link (i.e., to 3.3 VDC)?

The reason I ask is because I am trying to utilize some spare pins on an existing connector. I have 4 signal pins plus a ground pin available, but no 3.3 VDC ref available.

For the SWD connection I believe I need:

SWDIO
SWCLK
SWO
!RESET

as a minimum set.

Thanks in advance,

Loren

SEGGER - Nino

Super Moderator

Date of registration: Jan 2nd 2017

Posts: 325

2

Tuesday, November 14th 2017, 4:53pm

Hi Loren,

Thank you for your inquiry.

Quoted

1. I believe this is actually an input used to set the SWxx pins' signal level. Do I understand this orrectly?

Correct.

Quoted

2. Do I need to provide a reference voltage or is there a way to manually set the Vref in the J-Link (i.e., to 3.3 VDC)?

There is no software option to set the VTref value but we offer a Supply Adapter which eliminates the need of connecting VTref to the target device: https://www.segger.com/products/debug-pr…supply-adapter/

Best regards,
Nino

Loren77

Beginner

Date of registration: Nov 12th 2017

Posts: 2

3

Tuesday, November 14th 2017, 5:28pm

Perfect! That is exactly what I need.

Thank you for the quick response.

Loren

SEGGER - Nino

Super Moderator

Date of registration: Jan 2nd 2017

Posts: 325

4

Wednesday, November 15th 2017, 12:22pm

Hi Loren,

Great to hear that you found what you are looking for.
I will consider this case as closed then.

Best regards,
Nino