Serial cable

From AlwaysInnovating

Serial cable on Touch Book v1

The Touch Book v1 (boards revision A1, B1, C1) already contains a level shifter and a SN65C3221EPW which can take up to 3.3V input. You therefore can just solder a serial cable to the Touch Book, without the need of any additional parts. See attached photo:

• P9 - Pin 1: Ground (square pin, towards the middle of the board)
• P9 - Pin 2: Tx (in the middle)
• P9 - Pin 3: Rx (towards the bottom of the board)

More precisely, on the picture:

• Orange cable (P9 - pin 1) is linked to pin 5 (ground) of the serial cable (pin 1 is the top left corner pin of the cable connector).
• Brown cable (P9 - pin 2) is linked to pin 3 (Tx) of the serial cable.
• White cable (P9 - pin 3) is linked to pin 2 (Rx) of the serial cable.

The settings required for the terminal program are 115200 8N1.

Serial cable on Touch Book v2 or Smart Book

The Touch Book v2 or the Smart Book (boards revision D4, D5, D6) contains a level shifter which can take up to 5V input. The Rx-5V and Tx-5V pins are aivalable both on the 40-pin connector (pin23: Tx-5V, Pin24: Rx-5V), as well as on an additional non-populated connector on the tablet SM04B-SRSS-TB P220 (Pin1: Rx-5V, Pin2: Tx-5V, Pin3: Gnd, Pin4: NC). We recommend that you connect those pins to DLP-TXRX-G available at Digikey 813-1017-ND.

Connect through minicom

To get a console on your PC, you need to connect the serial cable through a null modem to your PC for the Touch Book v1. You need the DLP-TXRX-G for he Touch Book v2 or the Smart Book.

PC (Linux or Windows or Mac) with a USB connector <=> USB to serial cable <=> null modem <=> custom cable <=> Touch Book v1

PC (Linux or Windows or Mac) with a USB connector <=> DLP-TXRX-G <=> custom cable <=> Touch Book v2 or Smart Book

On Windows, Mac, or Linux, you can use minicom to access the console. Install minicom on your machine, follow these steps in a Terminal as root:

• Setup your connection:

minicom -s

• Chose "Serial port setup" and enter "/dev/ttyUSB0" (considering you don't have any other serial cable connected):

• Once done, chose "Exit" in the main menu. It will launch the modem connection:

• After a few seconds, you should be able to access to a shell on your Touch Book:

Minicom has many options and functionalities; refer to the manpage and type Ctrl-A Z while running minicom.