Myke Predko

Adding a uSD Socket to a FRDM-K22F Board

Discussion created by Myke Predko on Jan 19, 2016
Latest reply on Feb 6, 2016 by Myke Predko

After having some difficulty putting the Molex SD-105027-001 socket onto a FRDM-K22F board, I wanted to impart a few hints to anybody that wants to do this on the K22F or any other boards which have the same footprint. 

 

Parts and tools:

  1. Load the attached application ("k22f_sd_card_01") which was created in KDS 3.1 with KSDK 1.3 and PE 3.0.2.  This will continuously poll the five pins associated with the SD card socket. 
  2. Make sure you have a good quality, Lead-Free solder, flux and soldering iron with a tiny tip as well as a larger tip for heavier soldering.  For the pins, I used a needle point soldering iron which goes down to 0.2mm (I did say "tiny").  This is not something that can be soldered on using a $20 Radio Shack soldering iron. 
  3. You might want to buy a few extra sockets as you will probably screw up the first one or two. 
  4. A 3" or so length of breadboard hook up wire. 
  5. A Digital Multi-Meter

 

Installation Steps:

  1. Familiarize yourself with the circuitry around the socket site (J8).  I recommend that you look at the K22F schematic top right hand corner of the third page.  Note that "G1" is actually between "P4" and "P5" which makes things a bit confusing. 
  2. Load the "k22f_sd_card_01 application into your K22F card and start checking the pins following the order given in the reference list below.  Insert the 3" piece of breadboard hook up wire to J25 pin 4 (Vcc) and touch the pads (and later the connector pins to make sure they are soldered and not shorted). 
  3. Put flux over each pin before putting down the socket.
  4. Solder the pins according the order set out in the reference list below.  Remember to test each pin after each pin is soldered (this is especially important for the four middle pins that are very close together).  After soldering the pins, test the connection by lightly touching the DMM probe or the breadboard wire to the socket pin to ensure there is a solder connection.  Pressing down hard could make it look like there's a solder connection where there actually isn't. 
  5. When the pins are soldered and the joints verified with no shorts to adjoining pins, solder the four main pins on the socket. 

 

Pin Reference:

This is starting with "P1" and then going down to "P8".  Because "G1" is located between "P4" and "P5", I found it easier to think of them in terms of pins 1 through 9.  The list below is the order I found it best to solder the pins:

   1.  "P1", use DMM to check connection to TP20.

   9.  "P8", use DMM to check connection to TP24. 

   4.  "P4", use DMM to check connection to 3.3V.  I check for connection to J6 pin 2.  Make sure not shorted to any other pins. 

   5.  "G1", use DMM to check connection to R42.  Run application and use breadboard wire to validate operation.  This is "SD_DETECT".

   6.  "P5", use DMM to check connection to R35.  Run application and use breadboard wire to validate operation.  This is "SD_CLK"

   3.  "P3", use DMM to check connection to R40.  Run application and use breadboard wire to validate operation.  This is "SD_DO"

   2.  "P2", use DMM to check connection to R37.  Run application and use breadboard wire to validate operation.  This is "SD_CS"

   7.  "P6", use DMM to check connection to Gnd.  I check for connection to J6 pin 1. 

   8.  "P7", use DMM to check connection to R49.  Run application and use breadboard wire to validate operation.  This is "SD_DI"

 

Good luck!

 

myke

Original Attachment has been moved to: k22f_sd_card_01.zip

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