TC4 Shield, Version 6

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Julius Watson
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TC4 Shield, Version 6 Figure 1 TC4 shield, fully built, configured for modern Arduino boards INTRODUCTION Version 6 of the TC4 shield has been upgraded to provide compatibility with a wider range of

1 TC4 Shield, Version 6 Figure 1 TC4 shield, fully built, configured for modern Arduino boards INTRODUCTION Version 6 of the TC4 shield has been upgraded to provide compatibility with a wider range of Arduino boards. Previous versions of the TC4 shield were designed to be compatible with Uno, Duemilanove, and Diecimila boards. Version 6 of the TC4 shield is now compatible with the Leonardo and Yun boards, as well as the Mega series. Version 6 remains compatible with the Uno series, but now is configured to exactly match the reconfigured stacking headers introduced with the R3. Backwards compatibility with legacy Arduino boards is provided with version 6 of the TC4 shield. Two clearly labeled solder jumpers are provided on the TC4 board to enable version 6 to work with Uno R2 and earlier, Duemilanove, and Diecimila boards. Version 6 boards can be ordered with the jumpers open (for newer boards) or closed (legacy) boards. Alternatively, it is a simple matter for the user to solder the jumpers themselves. BACKGROUND Several chips on the TC4 shield make use of the two-wire interface (TWI), also known as I2C. TWI makes use of two signals: serial clock (SCL) and serial data (SDA). Page 1

2 The analog digital converter (ADC) on the TC4, which reads microvolt signals from thermocouple sensors, is on the TWI bus. Similarly, the on-board ambient temperature sensor, which is required to help convert thermocouple signals into temperature readings, is a TWI chip. Finally, the TC4 s on-board 512 Kb EEPROM chip must have access to TWI s SCL and SDA signals. Figure 2 Arduino Uno R2 shows the older style header arrangement. SCL and SDA were provided at lower right on the A4 and A5 pins (base image courtesy of arduino.cc). On older Arduino boards, the SCL and SDA signals were mapped to the same pins as analog input signals A4 and A5 on the stacking headers. Specifically, the two pins in the southeast corner of the ANALOG IN header carried the SCL and SDA signals (see Figure 2). Page 2

3 Figure 3 Arduino Uno R3 shows the new style header pattern. The SCL and SDA signals are now at upper left (base image courtesy arduino.cc). As the Arduino line was extended, the designers found it necessary to move the SCL and SDA pins in order to support a broader family of ATMEL chips. So the Mega series of boards, the Uno (starting with R3), the Leonardo, the Yun, and other Arduino boards featured SCL and SDA pins on the far northwest corner of the board (see Figure 3). Figure 4 Arduino Leonardo, a newer board design, uses the header arrangement. The SCL and SDA pins are at upper left (base image courtesy arduino.cc). Page 3

4 As new boards became available, the stacking headers were expanded in size (see Figure 4). REDESIGN OF THE TC4 SHIELD TC4 shields prior to version 6 were directly compatible only with the original location of the SCL and SDA pins, and with the original stacking header configuration. Version 6 of the TC4 shield now supports the new locations of the SCL and SDA pins on the Arduino boards. It is also socketed to match the stacking header configuration found on the Uno R3 and other newer Arduino boards. Figure 5 TC4 shield with SMDs, version 6. Note that the solder jumpers are unsoldered, or open. This is the default configuration and supports Uno R3 and other newer Arduino boards. Users of legacy Arduino boards will still be able to use version 6 of the TC4 shield. Solder jumpers have been provided to allow the TC4 shield to access the SCL and SDA signals from their previous locations on A4 and A5. These simple solder jumpers can be installed at the factory before shipping, or they are very easy to install by the end user (see Figure 6 below). Page 4

5 Figure 6 TC4 shield with SMDs, version 6, with solder jumpers closed. Either a short piece of wire or a 0-ohm resistor can be used. In this configuration, the TC4 shield can be used with Arduino Uno R2 and older, Duemilanove, or Diecimila boards. Further, TC4 shield kits will include extra stacking headers to match either the older pattern, or the newer pattern. TC4 shields that are fully pre-built can be made with either system of headers. The default is the newer pattern, but the pattern will be provided upon request. Page 5

Arduino ADK Back. For information on using the board with the Android OS, see Google's ADK documentation.

Arduino ADK Back. For information on using the board with the Android OS, see Google's ADK documentation. Arduino ADK Arduino ADK R3 Front Arduino ADK R3 Back Arduino ADK Front Arduino ADK Back Overview The Arduino ADK is a microcontroller board based on the ATmega2560 (datasheet). It has a USB host interface