• Welcome to Andy's Workshop Forums. Please login or sign up.
 
March 29, 2024, 03:01:47 am

News:

SMF - Just Installed!


Show posts

This section allows you to view all posts made by this member. Note that you can only see posts made in areas you currently have access to.

Topics - stride

1
Hardware projects / GPIO Daughter Board Design
November 15, 2016, 06:08:44 am
Hello guys,

I'm a hobbyist mostly into software engineering, in addition into doing stuff on my DE2-115 Cyclone IV FPGA development board.
Unfortunately I have only rudimentary skills on electronics and analogous systems...

Anyhow, I recently made a wirespeed Ethernet packet sniffer on my development board, all pure logic - no CPU, big fun. I want to extend on that.

To learn a bit in the electronics area my goal now is to make a GPIO connected Daughter Board for the dev-kit, with a couple of Ethernet PHY's on it.


I've collected some information and installed TinyCAD for initial schematics.

GPIO header details from the DE2 manual: https://1drv.ms/i/s!AgV35ZnXdrAGghgrNiEJro6ZHbDj

The PHY chip I want to use: http://ww1.microchip.com/downloads/en/DeviceDoc/00002117C.pdf

Some manufacturer notes regarding power: http://ww1.microchip.com/downloads/en/AppNotes/ANLAN206.pdf
(I've opted for a solution as in Figure 11)

And finally, my initial schematics for power rails!  :) https://1drv.ms/i/s!AgV35ZnXdrAGghck96jI1YGuXq2z
(Please forgive my newbie mistakes)

I have a couple of questions that I would really appreciate help with:
- Since I'm not using the internal LDO, can I drop connecting it?
- Do I still need capacitors close to the power pins on the PHY chip? (As in Figure 7 from the app notes)
- What is the recommended way to wire up the DVDDH 3.3V?


With best Regards,

/stride