Ryan Tech Debug Clip (Assembly)

I was passed a Ryan Tech Debug Clip, a little board that allows you to connect to a Raspberry Pi via USB and the UART connections on it's GPIO this was due a good friend of mine Gadgetoid  had 2  from backing the Kickstarter.

I got interested in this watching Gadgetiod solder up the realising that it wasn't just another FTDI FT232R (being honest no happy with them after the hole bricking your device scandal, long story) or a Prolific PL-2303. It was using something unexpected Microchip MCP2221.

This little chip is not only a basic USB to UART bridge it can also bridge to GPIO, I2C and a tonne of other functionality. This really peaked my interest but that will be for a later blog post. This post i'm looking the assembly and what comes in the kit.

The Debug Clip clip comes in kit form requiring soldering together don't be too put off by this as all the joints are well spaced and it has plenty of guidance on the PCB's silkscreen.

In the kit is:

• PCB 
• A USB Type B socket 
• A two pin header with jumper 
• A green and a red LED
• A diode 
• Two Resistors of the same value 
• A fuse
• And the MCP2221 IC itself

One thing to note there was ESD foam protection on the legs of the IC. The foam would offer some electrical protection but the main reason would be to prevent the legs from being damaged in shipping.

The kit feels well thought through, the silkscreen on the PCB makes assembly even easier. There is a clear assembly guide provided by Ryan Tech but the Silk was so clear I didn't even need to look at it.

Assembling 

There are only a few things to make sure the orientation is correct the IC, the diode and the two LEDs.

I started assembling mine with the diode and resistors the have the lowest height to the board and folded the legs outwards before soldering. Then solder and trim with some side cutters.

The IC itself was next in height order it always worth making sure that the notch on the IC matches the pattern on the silkscreen.

Next I decided the the USB socket would be the best as it would create a flat surface to rest on this help with supporting the header when soldering that in, making sure to solder one contact on the header first and then reheat the join and push the part flush with the PCB (Mind you fingers it could get hot) 

Then it was onto the LEDs I chose the green one for RX and the red for TX. The positions are well marked with a little + for the positive side, which is the longer of the two LED leads.

The last component I assembled was the fuse then all was done for the moment.

All ready to plug into your Raspberry Pi and PC's USB port.

Installing drivers 

The Debug Clip's driver are not available in windows update at the moment but can be easily downloaded from the Microchip MCP2221 Product page.

If the device is working correctly it will appear in your device manager as other devices -> MCP2221 USB-I2C/UART Combo. Please note that the Clip will not work unless placed on a the Raspberry Pi's GPIO header, as it uses the Pi's 3.3v regulator to make sure the UART output is 3.3v so it doesn't damage the Pi. Also make sure that the Pi is on. 

So now go ahead and download the appropriate driver for you. I'm running a Windows 8.1 laptop so mine is the Windows Driver & Installer. 

Once downloaded open the archive and extract the files.

Navigate through the Driver Installation Tool and relevant 32 or 64 bit version and right click on the .inf file and select install from the menu. ( for me the installation tool didn't work )

 Then the device should appear in your device manager. This would be a really good point to  take note of which COM port the Clip appears on. (In my case it is assigned to COM10).

Using the Debug Clip

You are going to need a remote terminal program if you don't have one already, I use Putty and would recommend it for most users. I can be downloaded form here.

Once you have Putty running click on the Serial radio button and enter your COM number that you noted earlier and set the speed to 115200.

  

After clicking open a terminal window should appear and you will be asked to login with the normal user name a password.

Then you can just use it as though you are on the Raspberry Pi's command line.

I like the Debug Clip and it is nice to have the blinking green and red LEDs as the data is going back and fourth. It makes a good alternative to the FTDI or Prolific based boards that are out there. the assembly we very straight forward with no real issues. I give it 4 sparks, 3 for the device and and bonus for hack-ability. 

Then next Post do will be about modding and hacking the Debug Clip.

Pi Supply Gert VGA666 Assembly

So i have had this rocking around for some time now and I though it was high time that i gave it a test run.

This is the Gert VGA666 from Pi Supply. Designed a by Gert Van Loo of Raspberry Pi fame and ran as a successful kickstarter campaign back in October 2014 ( which is where mine has come from ).

The Gert VGA666 is a clever breakout board for the Raspberry Pi that allows it to use the GPIO header to generate a VGA signal.  This done with only 20 Resistors to mimic an analog signal  the VGA monitor use the obvious downside to this is that you use up a lot of the GPIO pins.

 Assembly       

On the Pi Supply product Page there is a link to a Github Repository that contains the instructions, some of the details on how it works and the required files to make the Pi work with it .

This is the what comes in the Kit:

• PCB 
• 20 Resistors 
• VGA socket 
• extended GPIO Connector 
• 2 Stickers and a Business card directing you towards the Pi Supply Website 

 This first thing I recommend doing is layout the parts and use a multimeter to check and label the tapes of resistors with all their values on the blue cased film resistor I find the colours hard to distinguish so i usually go straight for the multimeter as better choice than tying to remember my resistor band colours.

Labeling just helps when you come to the placing the parts. there should be:

• 2 x 120 ohm
• 3 x 500 ohm
• 3 x 1K ohm
• 3 x 2K ohm 
• 3 x 4K ohm
• 3x  8K ohm 
• 3 x 16K ohm 

I find the colour key in the instruction a little hard to follow so here is a Bill of Materials for the Resistors.

 Label            Resistance (ohms)

R2 -          500

R4 -          1000

R6 -          2000

R8 -          4000

R10 -        8000

R12 -        16000

R14 -        500

R16 -        1000

R18 -        2000

R20 -        4000

R22 -        8000

R24 -        16000

R26 -         500

R28 -        1000

R30 -        2000

R32 -        4000

R34 -        8000

R36 -        16000

R38 -          120

R40 -          120

Then it is just a case of placing all the resistors in their correct locations and fold the leads outward for me I like to place all the resistors first as this lest me see if I have any location wrong before soldering.

The back of the PCB becomes a bit of a 'Rats Nest' of resistor leads but there is plenty of space to solder them form the topside.

After soldering use a sideways cutter to trim all the leads if and if there are any joins looking a little low on solder apply more (best to do this as a better solder joint will give a more stable signal).

 now make sure the PCB is the correct way up for the next bit the instructions say 'The Connectors are at the same side as the surface mount resistors'

Then it is just a case of soldering first the GPIO connectors soldering one corner pin first to make sure that it is flush to the board then solder the rest of the pins you can insert the VGA connector if it makes the PCB a bit more stable to solder for you.

Then solder up the VGA connector.

ALL Assembled!

I will continue the software setup and testing in another post. Click Here