Manual
Table Of Contents
- Features
- Pin Configurations
- Description
- Architectural Overview
- General Purpose Register File
- ALU – Arithmetic Logic Unit
- In-System Programmable Flash Program Memory
- SRAM Data Memory
- Program and Data Addressing Modes
- Register Direct, Single Register Rd
- Register Direct, Two Registers Rd and Rr
- I/O Direct
- Data Direct
- Data Indirect with Displacement
- Data Indirect
- Data Indirect with Pre- decrement
- Data Indirect with Post- increment
- Constant Addressing Using the LPM Instruction
- Indirect Program Addressing, IJMP and ICALL
- Relative Program Addressing, RJMP and RCALL
- EEPROM Data Memory
- Memory Access Times and Instruction Execution Timing
- I/O Memory
- Reset and Interrupt Handling
- Reset Sources
- Power-on Reset
- External Reset
- Brown-out Detection
- Watchdog Reset
- MCU Status Register – MCUSR
- Interrupt Handling
- General Interrupt Mask Register – GIMSK
- General Interrupt Flag Register – GIFR
- Timer/Counter Interrupt Mask Register – TIMSK
- Timer/Counter Interrupt Flag Register – TIFR
- External Interrupts
- Interrupt Response Time
- MCU Control Register – MCUCR
- Sleep Modes
- Timer/Counters
- 16-bit Timer/Counter1
- Watchdog Timer
- EEPROM Read/Write Access
- Serial Peripheral Interface – SPI
- UART
- Analog Comparator
- Analog-to-Digital Converter
- I/O Ports
- Memory Programming
- Electrical Characteristics
- External Clock Drive Waveforms
- Typical Characteristics
- Register Summary
- Instruction Set Summary
- Ordering Information
- Packaging Information
- Errata for AT90S/LS4433 Rev. Rev. C/D/E/F
- Data Sheet ChangeLog for AT90S/LS4433
- Table of Contents
29
AT90S/LS4433
1042G–AVR–09/02
Timer/Counter Interrupt Flag
Register – TIFR
• Bit 7 – TOV1: Timer/Counter1 Overflow Flag
The TOV1 is set (one) when an overflow occurs in Timer/Counter1. TOV1 is cleared by
hardware when executing the corresponding interrupt handling vector. Alternatively,
TOV1 is cleared by writing a logical “1” to the flag. When the I-bit in SREG and TOIE1
(Timer/Counter1 Overflow Interrupt Enable) and TOV1 are set (one), the
Timer/Counter1 Overflow Interrupt is executed. In PWM mode, this bit is set when
Timer/Counter1 advances from $0000.
• Bit 6 – OCF1: Output Compare Flag 1
The OCF1 bit is set (one) when a Compare Match occurs between the Timer/Counter1
and the data in Output Compare Register 1 (OCR1). OCF1 is cleared by hardware when
executing the corresponding interrupt handling vector. Alternatively, OCF1 is cleared by
writing a logical “1” to the flag. When the I-bit in SREG and OCIE1 (Timer/Counter1
Compare Match Interrupt A Enable) and the OCF1 are set (one), the Timer/Counter1
Compare Match Interrupt is executed.
• Bits 5, 4 – Res: Reserved Bits
These bits are reserved bits in the AT90S4433 and always read as zero.
• Bit 3 – ICF1: Input Capture Flag 1
The ICF1 bit is set (one) to flag an Input Capture Event, indicating that the
Timer/Counter1 value has been transferred to the Input Capture Register (ICR1). ICF1
is cleared by hardware when executing the corresponding interrupt handling vector.
Alternatively, ICF1 is cleared by writing a logical “1” to the flag. When the SREG I-bit
and TICIE1 (Timer/Counter1 Input Capture Interrupt Enable) and ICF1 are set (one), the
Timer/Counter1 Capture Interrupt is executed.
• Bit 2 – Res: Reserved Bit
This bit is a reserved bit in the AT90S4433 and always reads as zero.
• Bit 1 – TOV0: Timer/Counter0 Overflow Flag
The bit TOV0 is set (one) when an overflow occurs in Timer/Counter0. TOV0 is cleared
by hardware when executing the corresponding interrupt handling vector. Alternatively,
TOV0 is cleared by writing a logical “1” to the flag. When the SREG I-bit and TOIE0
(Timer/Counter0 Overflow Interrupt Enable) and TOV0 are set (one), the
Timer/Counter0 Overflow Interrupt is executed.
• Bit 0 – Res: Reserved Bit
This bit is a reserved bit in the AT90S4433 and always reads as zero.
Bit 7 6 5 4 3 2 1 0
$38 ($58) TOV1 OCF1 ––ICF1 – TOV0 – TIFR
Read/Write R/W R/W R R R/W R R/W R
Initial Value 0 0 0 0 0 0 0 0