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Electronics => Projects, Designs, and Technical Stuff => Topic started by: martin321 on November 29, 2015, 03:50:40 AM

Title: GL823 sd card reader, no response
Post by: martin321 on November 29, 2015, 03:50:40 AM
Hi,

I am trying to get the GL823 card reader to work, but there is no response from the pcb when I plug in the USB cable.
There is 3.3v DVDD, 1.5v on LED pin and nothing on PMOS or AVDD.
No resistors placed at R1 to R5.

Received the design guide and datasheet from supplier. Think I have correctly copied it.
gl823_sch.pdf is the one I have made.

If anyone could help me out I would relay appreciate it.

Martin
Title: Re: GL823 sd card reader, no response
Post by: martin321 on December 07, 2015, 05:52:38 PM
Found the post linked under. Anyone that can see my error?

https://www.eevblog.com/forum/beginners/issues-with-breadboard-sd-card-reader/ (https://www.eevblog.com/forum/beginners/issues-with-breadboard-sd-card-reader/)
Title: Re: GL823 sd card reader, no response
Post by: mich41 on December 09, 2015, 12:37:04 AM
Quote
There is 3.3v DVDD, 1.5v on LED pin and nothing on PMOS or AVDD.
Hint: where the power to AVDD is supposed to come from? :)
Title: Re: GL823 sd card reader, no response
Post by: martin321 on December 09, 2015, 03:21:09 AM
Sorry, but I don't follow you.
Title: Re: GL823 sd card reader, no response
Post by: wraper on December 09, 2015, 03:32:58 AM
Sorry, but I don't follow you.
Do you expect AVDD to appear from nowhere  :palm:? It is externally connected to the chip. On the gl823_sch.pdf through the L1 inductor from the DVDD.
Title: Re: GL823 sd card reader, no response
Post by: mich41 on December 09, 2015, 03:59:40 AM
Well, DVDD does appear out of nowhere, so go figure :box:

Seriously though, page 16 of the datasheet kinda suggests that the internal 3.3V regulator outputs to DVDD and then note1 on page 12 tells that AVDD needs to be hooked up to that through a bead.