- •Features
 - •1. Pin Configurations
 - •1.1 Disclaimer
 - •2. Overview
 - •2.1 Block Diagram
 - •2.2 Pin Descriptions
 - •2.2.3 AVCC
 - •2.2.4 AGND
 - •2.2.5 Port A (PA7..PA0)
 - •2.2.6 Port B (PB7..PB0)
 - •2.2.7 RESET
 - •3. Resources
 - •4. About Code Examples
 - •5. AVR CPU Core
 - •5.1 Overview
 - •5.3 Status Register
 - •5.4 General Purpose Register File
 - •5.5 Stack Pointer
 - •5.6 Instruction Execution Timing
 - •5.7 Reset and Interrupt Handling
 - •5.7.1 Interrupt Response Time
 - •6. AVR Memories
 - •6.2 SRAM Data Memory
 - •6.2.1 Data Memory Access Times
 - •6.3 EEPROM Data Memory
 - •6.3.1 EEPROM Read/Write Access
 - •6.3.2 Atomic Byte Programming
 - •6.3.3 Split Byte Programming
 - •6.3.4 Erase
 - •6.3.5 Write
 - •6.3.6 Preventing EEPROM Corruption
 - •6.4 I/O Memory
 - •6.4.1 General Purpose I/O Registers
 - •6.5 Register Description
 - •7. System Clock and Clock Options
 - •7.1 Clock Systems and their Distribution
 - •7.2 Clock Sources
 - •7.3 Default Clock Source
 - •7.4 External Clock
 - •7.6 Calibrated Internal RC Oscillator
 - •7.7 128 kHz Internal Oscillator
 - •7.9 Crystal Oscillator
 - •7.10 Clock Output Buffer
 - •7.11 System Clock Prescaler
 - •7.11.1 Switching Time
 - •7.12 Register Description
 - •8. Power Management and Sleep Modes
 - •8.1 Sleep Modes
 - •8.2 Idle Mode
 - •8.3 ADC Noise Reduction Mode
 - •8.5 Standby Mode
 - •8.6 Power Reduction Register
 - •8.7 Minimizing Power Consumption
 - •8.7.1 Analog to Digital Converter
 - •8.7.2 Analog Comparator
 - •8.7.4 Internal Voltage Reference
 - •8.7.5 Watchdog Timer
 - •8.7.6 Port Pins
 - •8.8 Register Description
 - •9. System Control and Reset
 - •9.0.1 Resetting the AVR
 - •9.0.2 Reset Sources
 - •9.0.4 External Reset
 - •9.0.6 Watchdog Reset
 - •9.1 Internal Voltage Reference
 - •9.2 Watchdog Timer
 - •9.3 Timed Sequences for Changing the Configuration of the Watchdog Timer
 - •9.3.1 Safety Level 1
 - •9.3.2 Safety Level 2
 - •9.4 Register Description
 - •10. Interrupts
 - •10.1 Interrupt Vectors in ATtiny261/461/861
 - •11. External Interrupts
 - •11.1 Register Description
 - •12. I/O Ports
 - •12.1 Overview
 - •12.2 Ports as General Digital I/O
 - •12.2.1 Configuring the Pin
 - •12.2.2 Toggling the Pin
 - •12.2.3 Switching Between Input and Output
 - •12.2.4 Reading the Pin Value
 - •12.2.5 Digital Input Enable and Sleep Modes
 - •12.2.6 Unconnected Pins
 - •12.3 Alternate Port Functions
 - •12.3.1 Alternate Functions of Port B
 - •12.3.2 Alternate Functions of Port A
 - •12.4 Register Description
 - •13. Timer/Counter0 Prescaler
 - •13.0.1 Prescaler Reset
 - •13.0.2 External Clock Source
 - •13.1 Register Description
 - •14. Timer/Counter0
 - •14.1 Features
 - •14.2 Overview
 - •14.2.1 Registers
 - •14.2.2 Definitions
 - •14.3 Timer/Counter Clock Sources
 - •14.4 Counter Unit
 - •14.5 Modes of Operation
 - •14.5.1 Normal 8-bit Mode
 - •14.6 Input Capture Unit
 - •14.6.1 Input Capture Trigger Source
 - •14.6.2 Noise Canceler
 - •14.6.3 Using the Input Capture Unit
 - •14.7 Output Compare Unit
 - •14.7.1 Compare Match Blocking by TCNT0 Write
 - •14.7.2 Using the Output Compare Unit
 - •14.8 Timer/Counter Timing Diagrams
 - •14.9.1 Reusing the temporary high byte register
 - •14.10 Register Description
 - •15. Timer/Counter1 Prescaler
 - •15.0.1 Prescaler Reset
 - •15.0.2 Prescaler Initialization for Asynchronous Mode
 - •15.1 Register Description
 - •16. Timer/Counter1
 - •16.1 Features
 - •16.2 Overview
 - •16.2.1 Speed
 - •16.2.2 Accuracy
 - •16.2.3 Registers
 - •16.2.4 Synchronization
 - •16.2.5 Definitions
 - •16.3 Counter Unit
 - •16.3.1 Counter Initialization for Asynchronous Mode
 - •16.4 Output Compare Unit
 - •16.4.1 Force Output Compare
 - •16.4.2 Compare Match Blocking by TCNT1 Write
 - •16.4.3 Using the Output Compare Unit
 - •16.5 Dead Time Generator
 - •16.6 Compare Match Output Unit
 - •16.6.1 Compare Output Mode and Waveform Generation
 - •16.7 Modes of Operation
 - •16.7.1 Normal Mode
 - •16.7.3 Phase and Frequency Correct PWM Mode
 - •16.7.4 PWM6 Mode
 - •16.8 Timer/Counter Timing Diagrams
 - •16.9 Fault Protection Unit
 - •16.9.1 Fault Protection Trigger Source
 - •16.9.2 Noise Canceler
 - •16.10 Accessing 10-Bit Registers
 - •16.10.1 Reusing the temporary high byte register
 - •16.11 Register Description
 - •17.1 Features
 - •17.2 Overview
 - •17.3 Functional Descriptions
 - •17.3.2 SPI Master Operation Example
 - •17.3.3 SPI Slave Operation Example
 - •17.3.5 Start Condition Detector
 - •17.4 Alternative USI Usage
 - •17.4.4 Edge Triggered External Interrupt
 - •17.4.5 Software Interrupt
 - •17.5 Register Descriptions
 - •18.1 Register Description
 - •18.2 Analog Comparator Multiplexed Input
 - •19.1 Features
 - •19.2 Overview
 - •19.3 Operation
 - •19.4 Starting a Conversion
 - •19.5 Prescaling and Conversion Timing
 - •19.6 Changing Channel or Reference Selection
 - •19.6.1 ADC Input Channels
 - •19.6.2 ADC Voltage Reference
 - •19.7 ADC Noise Canceler
 - •19.7.1 Analog Input Circuitry
 - •19.7.2 Analog Noise Canceling Techniques
 - •19.7.3 ADC Accuracy Definitions
 - •19.8 ADC Conversion Result
 - •19.8.1 Single Ended Conversion
 - •19.8.2 Unipolar Differential Conversion
 - •19.8.3 Bipolar Differential Conversion
 - •19.9 Temperature Measurement
 - •19.10 Register Descriptin
 - •19.10.3.1 ADLAR = 0
 - •19.10.3.2 ADLAR = 1
 - •20. debugWIRE On-chip Debug System
 - •20.1 Features
 - •20.2 Overview
 - •20.3 Physical Interface
 - •20.4 Software Break Points
 - •20.5 Limitations of debugWIRE
 - •20.6 Register Description
 - •21. Self-Programming the Flash
 - •21.0.1 Performing Page Erase by SPM
 - •21.0.2 Filling the Temporary Buffer (Page Loading)
 - •21.0.3 Performing a Page Write
 - •21.1.1 EEPROM Write Prevents Writing to SPMCSR
 - •21.1.2 Reading the Fuse and Lock Bits from Software
 - •21.1.3 Preventing Flash Corruption
 - •21.1.4 Programming Time for Flash when Using SPM
 - •21.2 Register Description
 - •22. Memory Programming
 - •22.1 Program And Data Memory Lock Bits
 - •22.2 Fuse Bytes
 - •22.2.1 Latching of Fuses
 - •22.3 Signature Bytes
 - •22.4 Calibration Byte
 - •22.5 Page Size
 - •22.6 Parallel Programming Parameters, Pin Mapping, and Commands
 - •22.6.1 Signal Names
 - •22.7 Parallel Programming
 - •22.7.1 Enter Programming Mode
 - •22.7.2 Considerations for Efficient Programming
 - •22.7.3 Chip Erase
 - •22.7.4 Programming the Flash
 - •22.7.5 Programming the EEPROM
 - •22.7.6 Reading the Flash
 - •22.7.7 Reading the EEPROM
 - •22.7.8 Programming the Fuse Low Bits
 - •22.7.9 Programming the Fuse High Bits
 - •22.7.10 Programming the Extended Fuse Bits
 - •22.7.11 Programming the Lock Bits
 - •22.7.12 Reading the Fuse and Lock Bits
 - •22.7.13 Reading the Signature Bytes
 - •22.7.14 Reading the Calibration Byte
 - •22.8 Serial Downloading
 - •22.8.1 Serial Programming Algorithm
 - •22.8.2 Serial Programming Instruction set
 - •23. Electrical Characteristics
 - •23.1 Absolute Maximum Ratings*
 - •23.2 DC Characteristics
 - •23.3 Speed Grades
 - •23.4 Clock Characteristics
 - •23.4.1 Calibrated Internal RC Oscillator Accuracy
 - •23.4.2 External Clock Drive Waveforms
 - •23.4.3 External Clock Drive
 - •23.5 System and Reset Characteristics
 - •23.7 Parallel Programming Characteristics
 - •23.8 Serial Programming Characteristics
 - •24. Typical Characteristics
 - •24.1 Active Supply Current
 - •24.2 Idle Supply Current
 - •24.3 Supply Current of I/O modules
 - •Example
 - •24.6 Pin Driver Strength
 - •24.7 Pin Threshold and Hysteresis
 - •24.8 BOD Threshold and Analog Comparator Offset
 - •24.9 Internal Oscillator Speed
 - •24.10 Current Consumption of Peripheral Units
 - •24.11 Current Consumption in Reset and Reset Pulsewidth
 - •25. Register Summary
 - •26. Instruction Set Summary
 - •27. Ordering Information
 - •27.1 ATtiny261
 - •27.2 ATtiny461
 - •27.3 ATtiny861
 - •28. Packaging Information
 - •29. Errata
 - •29.1 Errata ATtiny261
 - •29.2 Errata ATtiny461
 - •29.3 Errata ATtiny861
 - •30. Datasheet Revision History
 - •Table of Contents
 
ATtiny261/461/861
28. Packaging Information
28.132M1-A

 D 


 D1 

1  | 
	0  | 
|
2  | 
||
Pin 1 ID  | 
||
3  | 
E1 
 E
TOP VIEW
A2 
A
 K
P  | 
	
  | 
|
D2  | 
	
  | 
|
P  | 
	1  | 
|
2  | 
||
Pin #1 Notch  | 
||
  | 
(0.20 R) 3
E2
K
b  | 
	e  | 
	L  | 
BOTTOM VIEW
Note: JEDEC Standard MO-220, Fig. 2 (Anvil Singulation), VHHD-2.
SIDE VIEW
 A3


 A1

 0.08 C COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL  | 
	MIN  | 
	NOM  | 
	MAX  | 
	NOTE  | 
A  | 
	0.80  | 
	0.90  | 
	1.00  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
A1  | 
	–  | 
	0.02  | 
	0.05  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
A2  | 
	–  | 
	0.65  | 
	1.00  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
A3  | 
	
  | 
	0.20 REF  | 
	
  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
b  | 
	0.18  | 
	0.23  | 
	0.30  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
D  | 
	
  | 
	5.00 BSC  | 
	
  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
D1  | 
	
  | 
	4.75 BSC  | 
	
  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
D2  | 
	2.95  | 
	3.10  | 
	3.25  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
E  | 
	
  | 
	5.00 BSC  | 
	
  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
E1  | 
	
  | 
	4.75BSC  | 
	
  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
E2  | 
	2.95  | 
	3.10  | 
	3.25  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
e  | 
	
  | 
	0.50 BSC  | 
	
  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
L  | 
	0.30  | 
	0.40  | 
	0.50  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
P  | 
	–  | 
	–  | 
	0.60  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
0  | 
	–  | 
	–  | 
	12o  | 
	
  | 
K  | 
	0.20  | 
	–  | 
	–  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
	
  | 
8/19/04
TITLE
  | 
	2325 Orchard Parkway  | 
	32M1-A, 32-pad, 5 x 5 x 1.0 mm Body, Lead Pitch 0.50 mm,  | 
  | 
	San Jose, CA 95131  | 
|
R  | 
	3.10 mm Exposed Pad, Micro Lead Frame Package (MLF)  | 
DRAWING NO. REV.
32M1-A D
225
2588B–AVR–11/06
28.220P3
D
PIN 1
E1
A
SEATING PLANE
A1
L
B
B1
e
E
C 
 eC
eB
Notes: 1. This package conforms to JEDEC reference MS-001, Variation AD.
2.Dimensions D and E1 do not include mold Flash or Protrusion. Mold Flash or Protrusion shall not exceed 0.25 mm (0.010").
COMMON DIMENSIONS
(Unit of Measure = mm)
SYMBOL  | 
	MIN  | 
	NOM  | 
	MAX  | 
	NOTE  | 
A  | 
	–  | 
	–  | 
	5.334  | 
	
  | 
A1  | 
	0.381  | 
	–  | 
	–  | 
	
  | 
D  | 
	25.493  | 
	–  | 
	25.984  | 
	Note 2  | 
E  | 
	7.620  | 
	–  | 
	8.255  | 
	
  | 
E1  | 
	6.096  | 
	–  | 
	7.112  | 
	Note 2  | 
B  | 
	0.356  | 
	–  | 
	0.559  | 
	
  | 
B1  | 
	1.270  | 
	–  | 
	1.551  | 
	
  | 
L  | 
	2.921  | 
	–  | 
	3.810  | 
	
  | 
C  | 
	0.203  | 
	–  | 
	0.356  | 
	
  | 
eB  | 
	–  | 
	–  | 
	10.922  | 
	
  | 
eC  | 
	0.000  | 
	–  | 
	1.524  | 
	
  | 
  | 
	
  | 
	
  | 
	
  | 
|
e  | 
	
  | 
	2.540 TYP  | 
	
  | 
|
TITLE
  | 
	2325 Orchard Parkway  | 
	20P3, 20-lead (0.300"/7.62 mm Wide) Plastic Dual  | 
  | 
	San Jose, CA 95131  | 
|
R  | 
	Inline Package (PDIP)  | 
1/12/04
DRAWING NO. REV.
20P3 C
226 ATtiny261/461/861
2588B–AVR–11/06
ATtiny261/461/861
28.320S2
227
2588B–AVR–11/06
