AT91SAM7S256C-MU Atmel, AT91SAM7S256C-MU Datasheet - Page 43

• 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

11.2.4.1
6175K–ATARM–30-Aug-10
Modes and Exception Handling
Table 11-1.
Registers R0 to R7 are unbanked registers. This means that each of them refers to the same 32-
bit physical register in all processor modes. They are general-purpose registers, with no special
uses managed by the architecture, and can be used wherever an instruction allows a general-
purpose register to be specified.
Registers R8 to R14 are banked registers. This means that each of them depends on the current
mode of the processor.
All exceptions have banked registers for R14 and R13.
After an exception, R14 holds the return address for exception processing. This address is used
to return after the exception is processed, as well as to address the instruction that caused the
exception.
R13 is banked across exception modes to provide each exception handler with a private stack
pointer.
The fast interrupt mode also banks registers 8 to 12 so that interrupt processing can begin with-
out having to save these registers.
User and
System Mode
R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
PC
CPSR
ARM7TDMI ARM Modes and Registers Layout
Supervisor
Mode
R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13_SVC
R14_SVC
PC
CPSR
SPSR_SVC
Abort Mode
R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13_ABORT
R14_ABORT
PC
CPSR
SPSR_ABORT
AT91SAM7S Series Preliminary
Undefined
Mode
R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13_UNDEF
R14_UNDEF
PC
CPSR
SPSR_UNDEF
Interrupt
Mode
R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13_IRQ
R14_IRQ
PC
CPSR
SPSR_IRQ
Mode-specific banked registers
Fast Interrupt
Mode
R0
R1
R2
R3
R4
R5
R6
R7
R8_FIQ
R9_FIQ
R10_FIQ
R11_FIQ
R12_FIQ
R13_FIQ
R14_FIQ
PC
CPSR
SPSR_FIQ
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