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
69
AT90S/LS4433
1042G–AVR–09/02
• Bit 5 – ADFR: ADC Free Run Select
When this bit is set (one), the ADC operates in Free Run mode. In this mode, the ADC
samples and updates the Data Registers continuously. Clearing this bit (zero) will termi-
nate Free Run mode.
• Bit 4 – ADIF: ADC Interrupt Flag
This bit is set (one) when an ADC conversion completes and the Data Registers are
updated. The ADC Conversion Complete interrupt is executed if the ADIE bit and the I-
bit in SREG are set (one). ADIF is cleared by hardware when executing the correspond-
ing interrupt handling vector. Alternatively, ADIF is cleared by writing a logical “1” to the
flag. Beware that if doing a Read-Modify-Write on ADCSR, a pending interrupt can be
disabled. This also applies if the SBI and CBI instructions are used.
• Bit 3 – ADIE: ADC Interrupt Enable
When this bit is set (one) and the I-bit in SREG is set (one), the ADC Conversion Com-
plete interrupt is activated.
• Bits 2..0 – ADPS2..ADPS0: ADC Prescaler Select Bits
These bits determine the division factor between the XTAL frequency and the input
clock to the ADC.
ADC Data Register – ADCL
AND ADCH
When an ADC conversion is complete, the result is found in these two registers. In Free
Run mode, it is essential that both registers are read and that ADCL is read before
ADCH.
Table 22. ADC Prescaler Selections
ADPS2 ADPS1 ADPS0 Division Factor
000 2
001 2
010 4
011 8
100 16
101 32
110 64
111 128
Bit 151413121110 9 8
$05 ($25) ––––––ADC9 ADC8 ADCH
$04 ($26) ADC7 ADC6 ADC5 ADC4 ADC3 ADC2 ADC1 ADC0 ADCL
76543210
Read/Write R RRRRRRR
RRRRRRRR
InitialValue00000000
00000000