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
12
AT90S/LS4433
1042G–AVR–09/02
The direct addressing reaches the entire data space. The Indirect with Displacement
mode features 63 address locations reached from the base address given by the Y- or
Z-register.
When using register indirect addressing modes with automatic pre-decrement and post-
increment, the address registers X, Y, and Z are decremented and incremented.
The 32 general purpose working registers, 64 I/O Registers and the 128 bytes of inter-
nal data SRAM in the AT90S4433 are all accessible through all these addressing
modes.
See the next section for a detailed description of the different addressing modes.
Program and Data
Addressing Modes
The AT90S4433 AVR RISC microcontroller supports powerful and efficient addressing
modes for access to the Flash Program memory, SRAM, Register File, and I/O data
memory. This section describes the different addressing modes supported by the AVR
architecture. In the figures, OP means the operation code part of the instruction word.
To simplify, not all figures show the exact location of the addressing bits.
Register Direct, Single
Register Rd
Figure 10. Direct Single Register Addressing
The operand is contained in register d (Rd).
Register Direct, Two Registers
Rd and Rr
Figure 11. Direct Register Addressing, Two Registers
Operands are contained in registers r (Rr) and d (Rd). The result is stored in register d
(Rd).