-D_XDATA_START=0x0000 -D_XDATA_END=0x07FF
#pragma location = "MY_SEGMENT" __xdata int my_var; // Interrupt service routine #pragma vector = 0x23 // UART interrupt vector (address 0x23) __interrupt void uart_isr(void) // no prologue/epilogue overhead if __irq iar embedded workbench for 8051
-D_DATA_START=0x0000 -D_DATA_END=0x007F
// Timer0 interrupt vector (IAR uses interrupt number, not address) #pragma vector = 1 // Timer0 overflow interrupt (address 0x000B) __interrupt void timer0_isr(void) TF0 = 0; // clear flag TH0 = 0xFC; // reload for 1ms @ 11.0592 MHz TL0 = 0x66; IAR supports five memory models: // Inline assembly
It is widely used in legacy and modern embedded systems (industrial control, IoT sensors, automotive, medical devices) requiring extreme code density and real-time performance. | Feature | Description | |---------|-------------| | Compiler | Optimizing C/C++ compiler with extensive 8051-specific extensions | | Linker | Flexible segment management for near/far/idata/xdata/code memory | | Debugger | C-spy with hardware support (JTAG, SDI, ROM-monitor) | | Memory Models | Small, Medium, Compact, Large, Huge | | Bank Switching | Support for up to 2 MB code banking | | Peripheral Support | SFR (Special Function Register) definitions for 1000+ devices | | RTOS Awareness | For embOS, FreeRTOS, TI-RTOS | | Code Size | Industry-leading density (often 15–30% smaller than Keil) | 3. Memory Model Selection (Critical for 8051) The 8051 has Harvard architecture with separate memory spaces. IAR supports five memory models: // clear flag TH0 = 0xFC
// Inline assembly __asm("MOV A, #0x55"); __asm("MOV P1, A");
// Device-specific for AT89S52 #define F_CPU 11059200UL