ATTINY20-EK1 Atmel, ATTINY20-EK1 Datasheet - Page 139

• Manufacturer Part Number: ATTINY20-EK1
• Description: KIT EVAL TOUCH ATTINY20
• Manufacturer: Atmel

Specifications of ATTINY20-EK1

• Sensor Type: *
• Sensing Range: *
• Interface: *
• Sensitivity: *
• Voltage - Supply: *
• Embedded: *
• Utilized Ic / Part: *
• Silicon Manufacturer: Atmel
• Core Architecture: AVR
• Core Sub-architecture: TinyAVR
• Kit Contents: Board
• Svhc: No SVHC (15-Dec-2010)
• Mcu Supported Families: ATtiny20
• Tool / Board Applications: Microcontroller
• Rohs Compliant: Yes
• Tool Type: Development Kit
• Cpu Core: AVR 8
• Data Bus Width: 8 bit
• Processor To Be Evaluated: ATtiny20
• Interface Type: Touch
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

8235B–AVR–04/11
The TWI bus is a simple and efficient method of interconnecting multiple devices on a serial bus.
A device connected to the bus can be a master or slave, where the master controls the bus and
all communication.
Figure 17-1
Figure 17-1. TWI Bus Topology
A unique address is assigned to all slave devices connected to the bus, and the master will use
this to address a slave and initiate a data transaction. 7-bit or 10-bit addressing can be used.
Several masters can be connected to the same bus, and this is called a multi-master environ-
ment. An arbitration mechanism is provided for resolving bus ownership between masters since
only one master device may own the bus at any given time.
A device can contain both master and slave logic, and can emulate multiple slave devices by
responding to more than one address.
A master indicates the start of transaction by issuing a START condition (S) on the bus. An
address packet with a slave address (ADDRESS) and an indication whether the master wishes
to read or write data (R/W), is then sent. After all data packets (DATA) are transferred, the mas-
ter issues a STOP condition (P) on the bus to end the transaction. The receiver must
acknowledge (A) or not-acknowledge (A) each byte received.
Figure 17-2
Figure 17-2. Basic TWI Transaction Diagram Topology
illustrates the TWI bus topology.
shows a TWI transaction.
ATtiny20
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