[NTLK] DIY N2x00 Serial to USB Internal Connector

[Igor Bertolucci]

Hello Everyone,

Here is a little more detail on the internal USB connector that I added to my Shrinking Newt project. The device is called SparkFun FTDI Basic Breakout and here is a link to Amazon where I bought mine: https://www.amazon.com/dp/B0068QKQEA/ref=cm_sw_em_r_mt_dp_U_HLEWCbGGGVPWY

It is a tiny FTDI serial to USB converter measuring only 22mm x 15mm and only costs $17.50. I purchased the 5V version because I also needed it to power the LiPo charger I mounted on the back of my project. There is also a 3V version available. If you are using this only as a data port I think either one will be fine since you will not be connecting the voltage pin anywhere, just the data pins and the ground.

For the wire I used this 30 gauge silicon wire that has worked great: https://www.amazon.com/gp/product/B01M70EDCW/ref=ppx_yo_dt_b_asin_title_o01_s00?ie=UTF8&psc=1

Finally for the pins that go into the internal interconnect port I ordered samples from Samtec.com : https://www.samtec.com/products/fte

The connector description is FTE-116-01-G-DV. This is the 16x2 pin male plug that would snap into the internal interconnect port. Since the connector was too thick for my project and since I only needed to connect 4 of the 32 pins, I pulled the tiny little pins off the connector, shortened them about 1/32" and soldered the wires directly to these tiny pins, which I then inserted directly into the correct pin locations on the interconnect port (with tweezer pliers). You could also probably insert the 30 gauge wires directly into the pin holes as well without the need of the FTE-116-01-G-DV pins.

I would like to direct everyone to this wonderful blog written by Jake Bordens where I gathered much of my information needed for this aspect of my project: http://retronewton.blogspot.com/2015/01/the-internal-interconnect-port.html

After soldering all five wires (4 communication and one ground) you just have to insert them into their proper locations. These are as follows:

INTERCONNECT PORT            ->               SPARKFUN FTDI

Transmit Data               3TXD  ->  RXI       Receive Data
Receive Data                 3RXD  ->  TX0      Transmit Data
Request To Send           3RTS  ->  CTS      Clear To Send
Data Terminal Ready   3DTR  ->  DTR     Data Terminal Ready
Ground                           GND   ->  GND    Ground

The location of the pins on the Internal Interconnect Port from the top right as follows:

3TXD  ->  PIN 2
3RXD  ->  PIN 3
3RTS  ->  PIN 4
3DTR  ->  PIN 6
GND   ->  PIN 16

Here is a link to a photo where you can see the pin connections: https://flic.kr/p/2fAwQyA

For my Shrinking Newt project I have (for now) hot glued the SparkFun FTDI board to the Newton motherboard and put a piece of tape on the internal interconnect board.

...And that is basically it. I would like to thank Jake Bordens for his great blog where I learned most of what I needed to know for this project.

Hopefully this will be of interest and help for others as well. The process is not particularly difficult, however the pins and wires we are working with here are very small - that is really the only challenge.

Let me know if anybody has any questions.

One last thing, to actually use the port you will need to have the SerChan3115200.pgk installed on your Newton. This will activate the internal serial port and you will be able to communicate with NCX (Newton Connection) on a Mac at 115200 baud. I have yet to find a way to get Apples Newton Connection Utilities working at this speed under Windows 10 – it only gives me the option of 38400. If someone know how to do this please let me know.

Cheers,
Igor