UThing

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uThing

IMG 20150128 112416.jpg

The uThing is one of Bright Things core modules. It consists of a powerful MIPS processor running Ionic and a Real-time Atmel AVR microcontroller for controlling analogue and digital input/output.

The module is designed to be usable in a breadboard for rapid prototyping and at the same time be suitable for production systems.

Architecture

The internal architecture of the uThing is as follows:

UThing Block Diagram.svg

The architecture is build around two micro processors: a MIPS 24k and an AVR Atmega. The MIPS processor is intended to control networking, while the Atmega is intended to control analog and digital I/O in real-time. The two architectures can communicate with each other using either I2C, SPI or Serial communication.

Header

Overview

HEADER A HEADER B
PIN Name Description Description Name PIN
1 V+ Supply voltage Ground GND 1
2 3.3V Regulated 3.3V Supply/Output Digital I/O 7 D7 2
3 5V Regulated 5V Output A/D Voltage reference AREF 3
4 12V Regulated 12V OUT Analog out 5 A5 4
5 CTX Serial console TX Analog out 4 A4 5
6 CRX Serial console RX Analog out 3 A3 6
7 P0TX- Ethernet 0 TX- Analog out 2 A2 7
8 P0TX+ Ethernet 0 TX+ Analog out 1 A1 8
9 2V Regulated 2V Analog out 0 A0 9
10 P0RX- Ethernet 0 RX- Digital I/O 5 D5 10
11 P0RX+ Ethernet 0 RX+ I/O 10 IO10 11
12 GND Ground I/O 9 IO9 12
13 P4TX- Ethernet 4 TX- I/O 8 IO8 13
14 P4TX+ Ethernet 4 TX+ D7 D7 14
15 2V Regulated 2V D6 D6 15
16 P4RX- Ethernet 4 RX- D5 D5 16
17 P4RX+ Ethernet 4 RX+ D4 D4 17
18 LED0 LED0/WLAN TX Led TXLED 18
19 LED1 LED1/USB RX Led RXLED 19
20 LED5 LED5 D3 D3 20
21 LED7 LED7 D2 D2 21
22 AVRRST AVR Reset SDL 22
23 USB1- USB- IO11 23
24 USB1+ USB+ MOSI 24
25 GPIO12 GPIO 12 MISO 25
26 GPIO11 GPIO 11 SCLK 26

Pin Description

GND

Should be connected to ground.

V+

If a pThing module is mounted, DC power can be connected to this pin. Alternatively, the uThing module can be powered by a regulated 3.3 V supply on the +3.3V pin AND a regulated 5V on the +5V pin.

MIPS

The MIPS part of the uTHing is build around an Atheros AR9331 SOC.

AVR

To be added

Communication

I²C

The MIPS and the Atmega processors are connected to a shared I²C bus. This bus can be used for communication between the processors or it can be used for communicating with external devices (or adapter boards).

SPI

To be added

Serial

The uThing includes a number of different serial busses. Both the MIPS and the Atmega processor includes an internal UART which are available on the external pin connectors of the module. If serial communication between the processors is required, these pins can simply be tied together. Alternatively a virtual USB UART connection is included. The USB port of the AVR processor is tied to the USB hub of the MIPS.

USB

The Atmega USB port is connected to a USB electronics switch, so that if nothing is connected to the USB Device connector, then the Atmega USB port is connected to the MIPS USB Host Hub and will be seen as a emulated UART in Linux. If one connects another USB Host (such as a computer) to the USB Device connector, then the electronci switch will make the USB of Atmega to connect to it instead. This way, you can use the Arduino IDE directly to the Atmega of the uThing. It is Arduino Leonardo compatible, and the USB either shows up directly as a serial port, or you might need to install a driver for it.

Gallery

Prototype Rev-D

Prototype Rev-B