AT91SAM9260B-QU Atmel, AT91SAM9260B-QU Datasheet - Page 38

• Manufacturer Part Number: AT91SAM9260B-QU
• Description: IC ARM9 MCU 208-PQFP
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM9260B-QU

• Core Processor: ARM9
• Core Size: 16/32-Bit
• Speed: 180MHz
• Connectivity: EBI/EMI, Ethernet, I²C, MMC, SPI, SSC, UART/USART, USB
• Peripherals: POR, WDT
• Number Of I /o: 96
• Program Memory Size: 32KB (32K x 8)
• Program Memory Type: ROM
• Ram Size: 24K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Data Converters: A/D 4x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 208-MQFP, 208-PQFP
• Package: 208PQFP
• Device Core: ARM926EJ-S
• Family Name: 91S
• Maximum Speed: 180 MHz
• Operating Supply Voltage: 1.8|3.3 V
• Data Bus Width: 32 Bit
• Number Of Programmable I/os: 96
• Interface Type: EBI/Ethernet/SPI/TWI/UART/USART/USB
• On-chip Adc: 4-chx10-bit
• Number Of Timers: 6
• Processor Series: AT91SAMx
• Core: ARM926EJ-S
• Data Ram Size: 8 KB
• Maximum Clock Frequency: 180 MHz
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• 3rd Party Development Tools: JTRACE-ARM-2M, MDK-ARM, RL-ARM, ULINK2
• Development Tools By Supplier: AT91SAM-ICE, AT91-ISP, AT91SAM9260-EK
• Minimum Operating Temperature: - 40 C
• Cpu Family: AT91
• Device Core Size: 32b
• Frequency (max): 180MHz
• Total Internal Ram Size: 8KB
• # I/os (max): 96
• Number Of Timers - General Purpose: 6
• Operating Supply Voltage (typ): 1.8/3.3V
• Operating Supply Voltage (max): 1.95/3.6V
• Operating Supply Voltage (min): 1.65/3V
• Instruction Set Architecture: RISC
• Operating Temp Range: -40C to 85C
• Operating Temperature Classification: Industrial
• Mounting: Surface Mount
• Pin Count: 208
• Package Type: PQFP
• For Use With: AT91SAM9260-EK - KIT EVAL FOR AT91SAM9260AT91SAM-ICE - EMULATOR FOR AT91 ARM7/ARM9
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Lead free / RoHS Compliant

10.4.8
38
Exception Modes and Handling
AT91SAM9260
ARM Instruction Set Overview
The BKPT, or Undefined instruction, and SWI exceptions are mutually exclusive.
There is one exception in the priority scheme though, when FIQs are enabled and a Data Abort
occurs at the same time as an FIQ, the ARM9EJ-S core enters the Data Abort handler, and pro-
ceeds immediately to FIQ vector. A normal return from the FIQ causes the Data Abort handler to
resume execution. Data Aborts must have higher priority than FIQs to ensure that the transfer
error does not escape detection.
Exceptions arise whenever the normal flow of a program must be halted temporarily, for exam-
ple, to service an interrupt from a peripheral.
When handling an ARM exception, the ARM9EJ-S core performs the following operations:
The register r13 is also banked across exception modes to provide each exception handler with
private stack pointer.
The ARM9EJ-S can also set the interrupt disable flags to prevent otherwise unmanageable
nesting of exceptions.
When an exception has completed, the exception handler must move both the return value in
the banked LR minus an offset to the PC and the SPSR to the CPSR. The offset value varies
according to the type of exception. This action restores both PC and the CPSR.
The fast interrupt mode has seven private registers r8 to r14 (banked registers) to reduce or
remove the requirement for register saving which minimizes the overhead of context switching.
The Prefetch Abort is one of the aborts that indicates that the current memory access cannot be
completed. When a Prefetch Abort occurs, the ARM9EJ-S marks the prefetched instruction as
invalid, but does not take the exception until the instruction reaches the Execute stage in the
pipeline. If the instruction is not executed, for example because a branch occurs while it is in the
pipeline, the abort does not take place.
The breakpoint (BKPT) instruction is a new feature of ARM9EJ-S that is destined to solve the
problem of the Prefetch Abort. A breakpoint instruction operates as though the instruction
caused a Prefetch Abort.
A breakpoint instruction does not cause the ARM9EJ-S to take the Prefetch Abort exception until
the instruction reaches the Execute stage of the pipeline. If the instruction is not executed, for
example because a branch occurs while it is in the pipeline, the breakpoint does not take place.
The ARM instruction set is divided into:
1. Preserves the address of the next instruction in the appropriate Link Register that cor-
2. Copies the CPSR into the appropriate SPSR.
3. Forces the CPSR mode bits to a value that depends on the exception.
4. Forces the PC to fetch the next instruction from the relevant exception vector.
• Branch instructions
responds to the new mode that has been entered. When the exception entry is from:
– ARM and Jazelle states, the ARM9EJ-S copies the address of the next instruction
– THUMB state, the ARM9EJ-S writes the value of the PC into LR, offset by a value
into LR (current PC(r15) + 4 or PC + 8 depending on the exception).
(current PC + 2, PC + 4 or PC + 8 depending on the exception) that causes the
program to resume from the correct place on return.
6221I–ATARM–17-Jul-09