~~META:
description abstract = usb serial interface
~~
====== Bus Pirate ======

Jonathan and Bill each have a [[http://hackaday.com/the-bus-pirate-universal-serial-interface/|Bus Pirate v3]]
====== Connecting to a Makerbot Cupcake ======

If you do not have a usb to ftdi cable, you can use a bus pirate. Here is how we setup a bus pirate v3 with firmware and bootloader 4.1 to a Cupcake ( bot 779, batch 11, motherboard firmware XXXX, plastruder firmware XXXX ).
===== Hardware Setup =====

Before plugging in the bus pirate, we need to make sure we are using +5v to communicate with the makerbot motherboard. Normally the bus pirate communicates with 3.3v, but luckily for us an internal pullup resistor can bring it up to 5v. Jump the Vup and +5v pins on the board.

There are only three more wires to connect, then we can setup the software. Connect ground to ground (pin 1 on the makerbot motherboard v1.2), BP **MISO** to Makerbot **RXD** (pin 5), and BP **MOSI** to Makerbot **TXD** (pin 4). This is because the Makerbot is based on a sanguino, so it is a DCE chip, and the bus pirate is DTE.

Now plug in the usb connection to the computer. The makerbot can be kept off until you open replicatorG.
===== Udev Rule =====
The bus pirate can show up as /dev/ttyUSBX, with X being any digit. A udev rule to always show up as /dev/buspirate is convenient.

  * Get the serial number of this particular bus pirate:

  # sudo udevadm info --attribute-walk -n /dev/ttyUSB0  | sed -n '/FTDI/,/serial/p'

  * And replace XXXXXX with that serial number:

  # sudo echo 'SUBSYSTEM=="tty", ATTRS{serial}=="XXXXXX", GROUP="users", MODE="0660", SYMLINK+="buspirate"' | sudo tee /etc/udev/rules.d/98-buspirate.rules

  * Reload the rules for udev, and re-plugin the bus pirate

  # sudo udevadm control --reload-rules

===== Connecting with minicom =====

Install minicom, and run

  # sudo minicom -s

* Navigate with the arrow keys and enter, choosing **Serial port setup** and pressing 'A' to change the **serial device** to '/dev/buspirate'

* Set **Hardware Flow Control** and **Software Flow Control** to off

* Exit, and choose **Save setup as dfl** so we can skip this part next time

Now exit and minicom should automagically connect to the bus pirate, giving you a command prompt.
===== Setting up a UART connection =====

Type //M// for the menu, then choose
  * //3// for **UART** mode
  * //7// for **38400** baud
  * //1// for **8, NONE** bits and parity
  * //1// for **1** stop bits 
  * //1// for **1** receive polarity
  * //1// for **Open drain (H=Hi-Z, L=GND)** output type

You should be back at the serial prompt.
  * Type CAPITAL //W// to set the **power supplies on**
  * Type //p// and then //2// to turn the **pullup on**
  * Type //(1)// to run the **UART bridge** macro

The bus pirate output has already been set to 38400 baud, but we now need to change the baud rate between the computer and bus pirate to 38400.
  * Type //B// and then //7// to set the bus pirate baud to **38400**. **Do not press space** yet!
  * In minicom, press //Control-A// and then //p// to access the **Comm Parameters** screen
  * Press //b// and then //b// again to bring the terminal baud rate down to **38400** (from 115200) and then press //enter//
  * Now you can press //space//

If all is good, the bottom of minicom should show we are communicating at **38400 8N1** and you are back to the regular menu.
  * In minicom, press //Control-A// then CAPITAL //X// to **exit without reset**

===== Final steps =====

Congratulations, you are now ready to use replicatorG to test your makerbot!

===== Updating Firmware =====

When updating the plastruder firmware, make sure to be at **19200** baud rate!

{{tag>projects makerbot arduino}}