at91cap7e ATMEL Corporation, at91cap7e Datasheet - Page 56

• Manufacturer Part Number: at91cap7e
• Description: Customizable Microcontroller
• Manufacturer: ATMEL Corporation

12.2.4
56
AT91CAP7E
ARM7TDMI Registers
modes, or privileged modes, are entered in order to service interrupts or exceptions, or to
access protected resources.
The ARM7TDMI processor has a total of 37registers:
These registers are not accessible at the same time. The processor state and operating mode
determine which registers are available to the programmer.
At any one time 16 registers are visible to the user. The remainder are synonyms used to speed
up exception processing.
Register 15 is the Program Counter (PC) and can be used in all instructions to reference data
relative to the current instruction.
R14 holds the return address after a subroutine call.
R13 is used (by software convention) as a stack pointer.
Table 12-1.
User and
System Mode
R0
R1
R2
R3
R4
R5
R6
R7
R8
R9
R10
R11
R12
R13
R14
PC
CPSR
• 31 general-purpose 32-bit registers
• 6 status registers
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
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
8549A–CAP–10/08