Datasheet
Table Of Contents
- Features
- 1. Pin Configurations
- 2. Overview
- 3. About
- 4. CPU Core
- 5. Memories
- 6. Clock System
- 7. Power Management and Sleep Modes
- 8. System Control and Reset
- 9. Interrupts
- 10. I/O Ports
- 11. 8-bit Timer/Counter0 with PWM
- 11.1 Features
- 11.2 Overview
- 11.3 Clock Sources
- 11.4 Counter Unit
- 11.5 Output Compare Unit
- 11.6 Compare Match Output Unit
- 11.7 Modes of Operation
- 11.8 Timer/Counter Timing Diagrams
- 11.9 Register Description
- 11.9.1 TCCR0A – Timer/Counter Control Register A
- 11.9.2 TCCR0B – Timer/Counter Control Register B
- 11.9.3 TCNT0 – Timer/Counter Register
- 11.9.4 OCR0A – Output Compare Register A
- 11.9.5 OCR0B – Output Compare Register B
- 11.9.6 TIMSK0 – Timer/Counter 0 Interrupt Mask Register
- 11.9.7 TIFR0 – Timer/Counter 0 Interrupt Flag Register
- 12. 16-bit Timer/Counter1
- 12.1 Features
- 12.2 Overview
- 12.3 Timer/Counter Clock Sources
- 12.4 Counter Unit
- 12.5 Input Capture Unit
- 12.6 Output Compare Units
- 12.7 Compare Match Output Unit
- 12.8 Modes of Operation
- 12.9 Timer/Counter Timing Diagrams
- 12.10 Accessing 16-bit Registers
- 12.11 Register Description
- 12.11.1 TCCR1A – Timer/Counter1 Control Register A
- 12.11.2 TCCR1B – Timer/Counter1 Control Register B
- 12.11.3 TCCR1C – Timer/Counter1 Control Register C
- 12.11.4 TCNT1H and TCNT1L – Timer/Counter1
- 12.11.5 OCR1AH and OCR1AL – Output Compare Register 1 A
- 12.11.6 OCR1BH and OCR1BL – Output Compare Register 1 B
- 12.11.7 ICR1H and ICR1L – Input Capture Register 1
- 12.11.8 TIMSK1 – Timer/Counter Interrupt Mask Register 1
- 12.11.9 TIFR1 – Timer/Counter Interrupt Flag Register 1
- 13. Timer/Counter Prescaler
- 14. USI – Universal Serial Interface
- 15. Analog Comparator
- 16. Analog to Digital Converter
- 16.1 Features
- 16.2 Overview
- 16.3 Operation
- 16.4 Starting a Conversion
- 16.5 Prescaling and Conversion Timing
- 16.6 Changing Channel or Reference Selection
- 16.7 ADC Noise Canceler
- 16.8 Analog Input Circuitry
- 16.9 Noise Canceling Techniques
- 16.10 ADC Accuracy Definitions
- 16.11 ADC Conversion Result
- 16.12 Temperature Measurement
- 16.13 Register Description
- 17. debugWIRE On-chip Debug System
- 18. Self-Programming the Flash
- 18.1 Performing Page Erase by SPM
- 18.2 Filling the Temporary Buffer (Page Loading)
- 18.3 Performing a Page Write
- 18.4 Addressing the Flash During Self-Programming
- 18.5 EEPROM Write Prevents Writing to SPMCSR
- 18.6 Reading Lock, Fuse and Signature Data from Software
- 18.7 Preventing Flash Corruption
- 18.8 Programming Time for Flash when Using SPM
- 18.9 Register Description
- 19. Memory Programming
- 19.1 Program And Data Memory Lock Bits
- 19.2 Fuse Bytes
- 19.3 Device Signature Imprint Table
- 19.4 Page Size
- 19.5 Serial Programming
- 19.6 High-voltage Serial Programming
- 19.7 High-Voltage Serial Programming Algorithm
- 19.7.1 Enter High-voltage Serial Programming Mode
- 19.7.2 Considerations for Efficient Programming
- 19.7.3 Chip Erase
- 19.7.4 Programming the Flash
- 19.7.5 Programming the EEPROM
- 19.7.6 Reading the Flash
- 19.7.7 Reading the EEPROM
- 19.7.8 Programming and Reading the Fuse and Lock Bits
- 19.7.9 Reading the Signature Bytes and Calibration Byte
- 19.7.10 Power-off sequence
- 20. Electrical Characteristics
- 21. Typical Characteristics
- 21.1 Supply Current of I/O Modules
- 21.2 Active Supply Current
- 21.3 Idle Supply Current
- 21.4 Power-down Supply Current
- 21.5 Standby Supply Current
- 21.6 Pin Pull-up
- 21.7 Pin Driver Strength
- 21.8 Pin Threshold and Hysteresis
- 21.9 BOD Threshold and Analog Comparator Offset
- 21.10 Internal Oscillator Speed
- 21.11 Current Consumption of Peripheral Units
- 21.12 Current Consumption in Reset and Reset Pulsewidth
- 22. Register Summary
- 23. Instruction Set Summary
- 24. Ordering Information
- 25. Packaging Information
- 26. Errata
- 27. Datasheet Revision History
- Table of Contents
42
8006K–AVR–10/10
ATtiny24/44/84
8.2.4 Watchdog Reset
When the Watchdog times out, it will generate a short reset pulse of one CK cycle duration. On
the falling edge of this pulse, the delay timer starts counting the Time-out period t
TOUT
. See
“Watchdog Timer” on page 42 for details on operation of the Watchdog Timer.
Figure 8-6. Watchdog Reset During Operation
8.3 Internal Voltage Reference
ATtiny24/44/84 features an internal bandgap reference. This reference is used for Brown-out
Detection, and it can be used as an input to the Analog Comparator or the ADC. The bandgap
voltage varies with supply voltage and temperature.
8.3.1 Voltage Reference Enable Signals and Start-up Time
The voltage reference has a start-up time that may influence the way it should be used. The
start-up time is given in “System and Reset Characteristics” on page 177. To save power, the
reference is not always turned on. The reference is on during the following situations:
1. When the BOD is enabled (by programming the BODLEVEL [2:0] Fuse).
2. When the internal reference is connected to the Analog Comparator (by setting the
ACBG bit in ACSR).
3. When the ADC is enabled.
Thus, when the BOD is not enabled, after setting the ACBG bit or enabling the ADC, the user
must always allow the reference to start up before the output from the Analog Comparator or
ADC is used. To reduce power consumption in Power-down mode, the user can avoid the three
conditions above to ensure that the reference is turned off before entering Power-down mode.
8.4 Watchdog Timer
The Watchdog Timer is clocked from an On-chip Oscillator which runs at 128 kHz. By controlling
the Watchdog Timer prescaler, the Watchdog Reset interval can be adjusted as shown in Table
8-3 on page 47. The WDR – Watchdog Reset – instruction resets the Watchdog Timer. The
Watchdog Timer is also reset when it is disabled and when a Chip Reset occurs. Ten different
clock cycle periods can be selected to determine the reset period. If the reset period expires
without another Watchdog Reset, the ATtiny24/44/84 resets and executes from the Reset Vec-
tor. For timing details on the Watchdog Reset, refer to Table 8-3 on page 47.
CK
CC