AT91SAM7S256C-MU Atmel, AT91SAM7S256C-MU Datasheet - Page 44

• Manufacturer Part Number: AT91SAM7S256C-MU
• Description: IC ARM7 MCU 32BIT 256K 64-QFN
• Manufacturer: Atmel
• Series: AT91SAMr

Specifications of AT91SAM7S256C-MU

• Core Processor: ARM7
• Core Size: 16/32-Bit
• Speed: 55MHz
• Connectivity: I²C, SPI, SSC, UART/USART, USB
• Peripherals: Brown-out Detect/Reset, DMA, POR, PWM, WDT
• Number Of I /o: 32
• Program Memory Size: 256KB (256K x 8)
• Program Memory Type: FLASH
• Ram Size: 64K x 8
• Voltage - Supply (vcc/vdd): 1.65 V ~ 1.95 V
• Data Converters: A/D 8x10b
• Oscillator Type: Internal
• Operating Temperature: -40°C ~ 85°C
• Package / Case: 64-VQFN Exposed Pad, 64-HVQFN, 64-SQFN, 64-DHVQFN
• Processor Series: AT91
• Core: ARM7TDMI
• Data Bus Width: 32 bit
• Data Ram Size: 64 KB
• Interface Type: SPI, TWI, USART, USB
• Maximum Clock Frequency: 55 MHz
• Number Of Programmable I/os: 32
• Number Of Timers: 5
• Operating Supply Voltage: 3.3 V
• Maximum Operating Temperature: + 85 C
• Mounting Style: SMD/SMT
• Minimum Operating Temperature: - 40 C
• Operating Temperature Range: - 40 C to + 85 C
• For Use With: AT91SAM-ICE - EMULATOR FOR AT91 ARM7/ARM9AT91SAM7S-EK - KIT EVAL FOR ARM AT91SAM7S
• Lead Free Status / RoHS Status: Lead free / RoHS Compliant
• Eeprom Size: -
• Lead Free Status / Rohs Status: Details
• Other names: AT91SAM7S256-MU; AT91SAM7S256-MU

11.2.4.2
11.2.4.3
11.2.5
44
AT91SAM7S Series Preliminary
ARM Instruction Set Overview
Status Registers
Exception Types
A seventh processing mode, System Mode, does not have any banked registers. It uses the
User Mode registers. System Mode runs tasks that require a privileged processor mode and
allows them to invoke all classes of exceptions.
All other processor states are held in status registers. The current operating processor status is
in the Current Program Status Register (CPSR). The CPSR holds:
All five exception modes also have a Saved Program Status Register (SPSR) that holds the
CPSR of the task immediately preceding the exception.
The ARM7TDMI
The types of exceptions are:
Exceptions are generated by internal and external sources.
More than one exception can occur in the same time.
When an exception occurs, the banked version of R14 and the SPSR for the exception mode
are used to save state.
To return after handling the exception, the SPSR is moved to the CPSR, and R14 is moved to
the PC. This can be done in two ways:
The ARM instruction set is divided into:
ARM instructions can be executed conditionally. Every instruction contains a 4-bit condition
code field (bit[31:28]).
Table 11-2
• four ALU flags (Negative, Zero, Carry, and Overflow)
• two interrupt disable bits (one for each type of interrupt)
• one bit to indicate ARM or Thumb execution
• five bits to encode the current processor mode
• fast interrupt (FIQ)
• normal interrupt (IRQ)
• memory aborts (used to implement memory protection or virtual memory)
• attempted execution of an undefined instruction
• software interrupts (SWIs)
• by using a data-processing instruction with the S-bit set, and the PC as the destination
• by using the Load Multiple with Restore CPSR instruction (LDM)
• Branch instructions
• Data processing instructions
• Status register transfer instructions
• Load and Store instructions
• Coprocessor instructions
• Exception-generating instructions
gives the ARM instruction mnemonic list.
supports five types of exception and a privileged processing mode for each type.
6175K–ATARM–30-Aug-10