ATTINY20-CCUR Atmel, ATTINY20-CCUR Datasheet - Page 139

• Manufacturer Part Number: ATTINY20-CCUR
• Description: MCU AVR 2KB FLASH 12MHZ 15UFBGA
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY20-CCUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 12MHz
• Connectivity: I²C, SPI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 12
• Program Memory Size: 2KB (1K x 16)
• Program Memory Type: FLASH
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 1.8 V ~ 5.5 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: *
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -

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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