Multi I/O (1-Wire / I2C / CAN) SnipCard with Galvanic Isolation for Archiduino system.
The Multi I/O (1-Wire / I2C / CAN) SnipCard allows to communicate with all 1-Wire devices made by Dallas Semiconductor and with I2C bus external devices. The SnipCard gives the possibility to connect the 1-Wire devices over two separated channels, or one single I2C communication bus (SCL and SDA). Both ways can be galvanically isolated with additional components (other versions of this SnipCard could be found in our shop). The SnipCard could also be used to drive two generic I/Os with buffering and ESD protection.
The core IC is the well known and highly reliable P82B96 bidirectional buffer made by Texas Instruments (or NXP). If chosen, the galvanic isolation is provided by the dual bidirectional isolator ADuM1250ARZ of Analog Devices, and the isolated supply is given by the DC/DC converter TME1205S made by Traco Power. The I/O plug dedicated to external connection is secured by a single-line ESD-protection diode (according to IEC 61000-4-2: ± 30 kV contact discharge, ± 30 kV air discharge) of the Vishay’s GSOT series.
In addition to the already described functions, there are several other ways to use this powerful SnipCard, as listed below:
- two I/O drivers for signals from 3 to 5 volts;
- two high speed 0-5 volts signal readers for industrial tachometers (or other square wave signals) up to 1,5 MHz (in the non-isolated version. If isolated the max frequency is limited to 1 MHz);
- two 0-5 volts low power PWM outputs;
Note: all listed operating modes are working even with the galvanic isolation mounted on the SnipCard.
Below two excerpts from Wikipedia in order to introduce the two main technologies on which this SnipCard is based.
1-Wire is a device communications bus system designed by Dallas Semiconductor Corp. that provides low-speed data, signaling, and power over a single signal. 1-Wire is similar in concept to I²C, but with lower data rates and longer range. It is typically used to communicate with small inexpensive devices such as digital thermometers and weather instruments. A network of 1-Wire devices with an associated master device is called a MicroLAN. One distinctive feature of the bus is the possibility of using only two wires: data and ground. To accomplish this, 1-Wire devices include an 800 pFcapacitor to store charge, and to power the device during periods when the data line is active. (link)
I²C (Inter-Integrated Circuit), pronounced I-squared-C, is a multi-master, multi-slave, single-ended, serialcomputer bus invented by Philips Semiconductor (now NXP Semiconductors). It is typically used for attaching lower-speed peripheral ICs to processors and microcontrollers. Alternatively I²C is spelled I2C (pronounced I-two-C) or IIC (pronounced I-I-C). Since October 10, 2006, no licensing fees are required to implement the I²C protocol. However, fees are still required to obtain I²C slave addresses allocated by NXP.
Several competitors, such as Siemens AG (later Infineon Technologies AG, now Intel mobile communications), NEC, Texas Instruments, STMicroelectronics (formerly SGS-Thomson), Motorola (later Freescale, now merged with NXP), Nordic Semiconductor and Intersil, have introduced compatible I²C products to the market since the mid-1990s. SMBus, defined by Intel in 1995, is a subset of I²C that defines the protocols more strictly. One purpose of SMBus is to promote robustness and interoperability. Accordingly, modern I²C systems incorporate policies and rules from SMBus, sometimes supporting both I²C and SMBus, requiring only minimal reconfiguration. (link)
The SnipCard comes with galvanic isolation configuration (with P82B96 driver).
Texas Instruments P82B96 datasheet
Analog Devices ADUM1250ARZ datasheet
Traco Power TME1205S datasheet
Vishay GSOT series single-line ESD protection – datasheet