ATTINY261-20MUR Atmel, ATTINY261-20MUR Datasheet - Page 125

• Manufacturer Part Number: ATTINY261-20MUR
• Description: IC MCU AVR 2K FLASH 20MHZ 32QFN
• Manufacturer: Atmel
• Series: AVR® ATtinyr

Specifications of ATTINY261-20MUR

• Core Processor: AVR
• Core Size: 8-Bit
• Speed: 20MHz
• Connectivity: USI
• Peripherals: Brown-out Detect/Reset, POR, PWM, WDT
• Number Of I /o: 16
• Program Memory Size: 2KB (1K x 16)
• Program Memory Type: FLASH
• Eeprom Size: 128 x 8
• Ram Size: 128 x 8
• Voltage - Supply (vcc/vdd): 2.7 V ~ 5.5 V
• Data Converters: A/D 11x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 32-VFQFN Exposed Pad
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant

13. USI – Universal Serial Interface
13.1
13.2
2588E–AVR–08/10
Features
Overview
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The Universal Serial Interface, or USI, provides the basic hardware resources needed for serial
communication. Combined with a minimum of control software, the USI allows significantly
higher transfer rates and uses less code space than solutions based on software only. Interrupts
are included to minimize the processor load.
A simplified block diagram of the USI is shown in
refer to
Register and bit locations are listed in the
Figure 13-1. Universal Serial Interface, Block Diagram
The 8-bit USI Data Register (USIDR) is directly accessible via the data bus and contains the
incoming and outgoing data. The register has no buffering so the data must be read as quickly
as possible to ensure that no data is lost. The data register is a serial shift register where the
most significant bit is connected to one of two output pins depending of the wire mode configura-
tion. A transparent latch between the output of the data register and the output pin delays the
change of data output to the opposite clock edge of the data input sampling. The serial input is
always sampled from the Data Input (DI) pin, regardless of the configuration.
Two-wire Synchronous Data Transfer (Master or Slave)
Three-wire Synchronous Data Transfer (Master or Slave)
Data Received Interrupt
Wakeup from Idle Mode
In Two-wire Mode: Wake-up from All Sleep Modes, Including Power-down Mode
Two-wire Start Condition Detector with Interrupt Capability
“Pinout ATtiny261/461/861 and ATtiny261V/461V/861V” on page
USIDR
USICR
USIDB
USISR
2
4-bit Counter
3
2
1
0
3
2
1
0
D Q
LE
“Register Descriptions” on page
[1]
TIM0 COMP
Figure 13-1
0
1
Two-wire Clock
Control Unit
For actual placement of I/O pins
CLOCK
HOLD
2. Device-specific I/O
132.
DO
DI/SDA
USCK/SCL
(Output only)
(Input/Open Drain)
(Input/Open Drain)
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