- •Contents
- •List of Tables
- •List of Figures
- •Preface
- •About this manual
- •Product revision status
- •Intended audience
- •Using this manual
- •Conventions
- •Additional reading
- •Feedback
- •Feedback on the product
- •Feedback on this book
- •Introduction
- •1.1 About the processor
- •1.2 Extensions to ARMv6
- •1.3 TrustZone security extensions
- •1.4.1 Instruction compression
- •1.4.2 The Thumb instruction set
- •1.4.3 Java bytecodes
- •1.5 Components of the processor
- •1.5.1 Integer core
- •1.5.2 Load Store Unit (LSU)
- •1.5.3 Prefetch unit
- •1.5.4 Memory system
- •1.5.5 AMBA AXI interface
- •1.5.6 Coprocessor interface
- •1.5.7 Debug
- •1.5.8 Instruction cycle summary and interlocks
- •1.5.9 System control
- •1.5.10 Interrupt handling
- •1.6 Power management
- •1.7 Configurable options
- •1.8 Pipeline stages
- •1.9 Typical pipeline operations
- •1.9.1 Instruction progression
- •1.10.1 Extended ARM instruction set summary
- •1.10.2 Thumb instruction set summary
- •1.11 Product revisions
- •Programmer’s Model
- •2.1 About the programmer’s model
- •2.2.1 TrustZone model
- •2.2.2 How the Secure model works
- •2.2.3 TrustZone write access disable
- •2.2.4 Secure Monitor bus
- •2.3 Processor operating states
- •2.3.1 Switching state
- •2.3.2 Interworking ARM and Thumb state
- •2.4 Instruction length
- •2.5 Data types
- •2.6 Memory formats
- •2.7 Addresses in a processor system
- •2.8 Operating modes
- •2.9 Registers
- •2.9.1 The ARM state core register set
- •2.9.2 The Thumb state core register set
- •2.9.3 Accessing high registers in Thumb state
- •2.9.4 ARM state and Thumb state registers relationship
- •2.10 The program status registers
- •2.10.1 The condition code flags
- •2.10.2 The Q flag
- •2.10.4 The GE[3:0] bits
- •2.10.7 The control bits
- •2.10.8 Modification of PSR bits by MSR instructions
- •2.10.9 Reserved bits
- •2.11 Additional instructions
- •2.11.1 Load or Store Byte Exclusive
- •2.11.2 Load or Store Halfword Exclusive
- •2.11.3 Load or Store Doubleword
- •2.11.4 CLREX
- •2.12 Exceptions
- •2.12.1 New instructions for exception handling
- •2.12.2 Exception entry and exit summary
- •2.12.3 Entering an ARM exception
- •2.12.4 Leaving an ARM exception
- •2.12.5 Reset
- •2.12.6 Fast interrupt request
- •2.12.7 Interrupt request
- •2.12.8 Low interrupt latency configuration
- •2.12.9 Interrupt latency example
- •2.12.10 Aborts
- •2.12.11 Imprecise Data Abort mask in the CPSR/SPSR
- •2.12.12 Supervisor call instruction
- •2.12.13 Secure Monitor Call (SMC)
- •2.12.14 Undefined instruction
- •2.12.15 Breakpoint instruction (BKPT)
- •2.12.16 Exception vectors
- •2.12.17 Exception priorities
- •2.13 Software considerations
- •2.13.1 Branch Target Address Cache flush
- •2.13.2 Waiting for DMA to complete
- •System Control Coprocessor
- •3.1 About the system control coprocessor
- •3.1.1 System control coprocessor functional groups
- •3.1.2 System control and configuration
- •3.1.3 MMU control and configuration
- •3.1.4 Cache control and configuration
- •3.1.5 TCM control and configuration
- •3.1.6 Cache Master Valid Registers
- •3.1.7 DMA control
- •3.1.8 System performance monitor
- •3.1.9 System validation
- •3.1.10 Use of the system control coprocessor
- •3.2 System control processor registers
- •3.2.1 Register allocation
- •3.2.2 c0, Main ID Register
- •3.2.3 c0, Cache Type Register
- •3.2.4 c0, TCM Status Register
- •3.2.5 c0, TLB Type Register
- •3.2.6 c0, CPUID registers
- •3.2.7 c1, Control Register
- •3.2.8 c1, Auxiliary Control Register
- •3.2.9 c1, Coprocessor Access Control Register
- •3.2.10 c1, Secure Configuration Register
- •3.2.11 c1, Secure Debug Enable Register
- •3.2.13 c2, Translation Table Base Register 0
- •3.2.14 c2, Translation Table Base Register 1
- •3.2.15 c2, Translation Table Base Control Register
- •3.2.16 c3, Domain Access Control Register
- •3.2.17 c5, Data Fault Status Register
- •3.2.18 c5, Instruction Fault Status Register
- •3.2.19 c6, Fault Address Register
- •3.2.20 c6, Watchpoint Fault Address Register
- •3.2.21 c6, Instruction Fault Address Register
- •3.2.22 c7, Cache operations
- •3.2.23 c8, TLB Operations Register
- •3.2.24 c9, Data and instruction cache lockdown registers
- •3.2.25 c9, Data TCM Region Register
- •3.2.26 c9, Instruction TCM Region Register
- •3.2.29 c9, TCM Selection Register
- •3.2.30 c9, Cache Behavior Override Register
- •3.2.31 c10, TLB Lockdown Register
- •3.2.32 c10, Memory region remap registers
- •3.2.33 c11, DMA identification and status registers
- •3.2.34 c11, DMA User Accessibility Register
- •3.2.35 c11, DMA Channel Number Register
- •3.2.36 c11, DMA enable registers
- •3.2.37 c11, DMA Control Register
- •3.2.38 c11, DMA Internal Start Address Register
- •3.2.39 c11, DMA External Start Address Register
- •3.2.40 c11, DMA Internal End Address Register
- •3.2.41 c11, DMA Channel Status Register
- •3.2.42 c11, DMA Context ID Register
- •3.2.44 c12, Monitor Vector Base Address Register
- •3.2.45 c12, Interrupt Status Register
- •3.2.46 c13, FCSE PID Register
- •3.2.47 c13, Context ID Register
- •3.2.48 c13, Thread and process ID registers
- •3.2.49 c15, Peripheral Port Memory Remap Register
- •3.2.51 c15, Performance Monitor Control Register
- •3.2.52 c15, Cycle Counter Register
- •3.2.53 c15, Count Register 0
- •3.2.54 c15, Count Register 1
- •3.2.55 c15, System Validation Counter Register
- •3.2.56 c15, System Validation Operations Register
- •3.2.57 c15, System Validation Cache Size Mask Register
- •3.2.58 c15, Instruction Cache Master Valid Register
- •3.2.59 c15, Data Cache Master Valid Register
- •3.2.60 c15, TLB lockdown access registers
- •Unaligned and Mixed-endian Data Access Support
- •4.2 Unaligned access support
- •4.2.1 Legacy support
- •4.2.2 ARMv6 extensions
- •4.2.3 Legacy and ARMv6 configurations
- •4.2.4 Legacy data access in ARMv6 (U=0)
- •4.2.5 Support for unaligned data access in ARMv6 (U=1)
- •4.2.6 ARMv6 unaligned data access restrictions
- •4.3 Endian support
- •4.3.1 Load unsigned byte, endian independent
- •4.3.2 Load signed byte, endian independent
- •4.3.3 Store byte, endian independent
- •4.4 Operation of unaligned accesses
- •4.5.1 Legacy fixed instruction and data endianness
- •4.5.3 Reset values of the U, B, and EE bits
- •4.6.1 All load and store operations
- •4.7 Instructions to change the CPSR E bit
- •Program Flow Prediction
- •5.1 About program flow prediction
- •5.2 Branch prediction
- •5.2.1 Enabling program flow prediction
- •5.2.2 Dynamic branch predictor
- •5.2.3 Static branch predictor
- •5.2.4 Branch folding
- •5.2.5 Incorrect predictions and correction
- •5.3 Return stack
- •5.4 Memory Barriers
- •5.4.1 Instruction Memory Barriers (IMBs)
- •5.5.1 Execution of IMB instructions
- •Memory Management Unit
- •6.1 About the MMU
- •6.2 TLB organization
- •6.2.1 MicroTLB
- •6.2.2 Main TLB
- •6.2.3 TLB control operations
- •6.2.5 Supersections
- •6.3 Memory access sequence
- •6.3.1 TLB match process
- •6.3.2 Virtual to physical translation mapping restrictions
- •6.4 Enabling and disabling the MMU
- •6.4.1 Enabling the MMU
- •6.4.2 Disabling the MMU
- •6.4.3 Behavior with MMU disabled
- •6.5 Memory access control
- •6.5.1 Domains
- •6.5.2 Access permissions
- •6.5.3 Execute never bits in the TLB entry
- •6.6 Memory region attributes
- •6.6.1 C and B bit, and type extension field encodings
- •6.6.2 Shared
- •6.6.3 NS attribute
- •6.7 Memory attributes and types
- •6.7.1 Normal memory attribute
- •6.7.2 Device memory attribute
- •6.7.3 Strongly Ordered memory attribute
- •6.7.4 Ordering requirements for memory accesses
- •6.7.5 Explicit Memory Barriers
- •6.7.6 Backwards compatibility
- •6.8 MMU aborts
- •6.8.1 External aborts
- •6.9 MMU fault checking
- •6.9.1 Fault checking sequence
- •6.9.2 Alignment fault
- •6.9.3 Translation fault
- •6.9.4 Access bit fault
- •6.9.5 Domain fault
- •6.9.6 Permission fault
- •6.9.7 Debug event
- •6.10 Fault status and address
- •6.11 Hardware page table translation
- •6.11.2 ARMv6 page table translation subpage AP bits disabled
- •6.11.3 Restrictions on page table mappings page coloring
- •6.12 MMU descriptors
- •Level One Memory System
- •7.1 About the level one memory system
- •7.2 Cache organization
- •7.2.1 Features of the cache system
- •7.2.2 Cache functional description
- •7.2.3 Cache control operations
- •7.2.4 Cache miss handling
- •7.2.5 Cache disabled behavior
- •7.2.6 Unexpected hit behavior
- •7.3.1 TCM behavior
- •7.3.2 Restriction on page table mappings
- •7.3.3 Restriction on page table attributes
- •7.5 TCM and cache interactions
- •7.5.1 Overlapping between TCM regions
- •7.5.2 DMA and core access arbitration
- •7.5.3 Instruction accesses to TCM
- •7.5.4 Data accesses to the Instruction TCM
- •7.6 Write buffer
- •Level Two Interface
- •8.1 About the level two interface
- •8.1.1 AXI parameters for the level 2 interconnect interfaces
- •8.2 Synchronization primitives
- •8.2.3 Example of LDREX and STREX usage
- •8.3 AXI control signals in the processor
- •8.3.1 Channel definition
- •8.3.2 Signal name suffixes
- •8.3.3 Address channel signals
- •8.4 Instruction Fetch Interface transfers
- •8.4.1 Cacheable fetches
- •8.4.2 Noncacheable fetches
- •8.5 Data Read/Write Interface transfers
- •8.5.1 Linefills
- •8.5.2 Noncacheable LDRB
- •8.5.3 Noncacheable LDRH
- •8.5.4 Noncacheable LDR or LDM1
- •8.5.5 Noncacheable LDRD or LDM2
- •8.5.6 Noncacheable LDM3
- •8.5.7 Noncacheable LDM4
- •8.5.8 Noncacheable LDM5
- •8.5.9 Noncacheable LDM6
- •8.5.10 Noncacheable LDM7
- •8.5.11 Noncacheable LDM8
- •8.5.12 Noncacheable LDM9
- •8.5.13 Noncacheable LDM10
- •8.5.14 Noncacheable LDM11
- •8.5.15 Noncacheable LDM12
- •8.5.16 Noncacheable LDM13
- •8.5.17 Noncacheable LDM14
- •8.5.18 Noncacheable LDM15
- •8.5.19 Noncacheable LDM16
- •8.6 Peripheral Interface transfers
- •8.7 Endianness
- •8.8 Locked access
- •Clocking and Resets
- •9.1 About clocking and resets
- •9.2 Clocking and resets with no IEM
- •9.2.1 Processor clocking with no IEM
- •9.2.2 Reset with no IEM
- •9.3 Clocking and resets with IEM
- •9.3.1 Processor clocking with IEM
- •9.3.2 Reset with IEM
- •9.4 Reset modes
- •9.4.1 Power-on reset
- •9.4.2 CP14 debug logic
- •9.4.3 Processor reset
- •9.4.4 DBGTAP reset
- •9.4.5 Normal operation
- •Power Control
- •10.1 About power control
- •10.2 Power management
- •10.2.1 Run mode
- •10.2.2 Standby mode
- •10.2.3 Shutdown mode
- •10.2.4 Dormant mode
- •10.2.5 Communication to the Power Management Controller
- •10.3 Intelligent Energy Management
- •10.3.1 Purpose of IEM
- •10.3.2 Structure of IEM
- •10.3.3 Operation of IEM
- •Coprocessor Interface
- •11.1 About the coprocessor interface
- •11.2 Coprocessor pipeline
- •11.2.1 Coprocessor instructions
- •11.2.2 Coprocessor control
- •11.2.3 Pipeline synchronization
- •11.2.4 Pipeline control
- •11.2.5 Instruction tagging
- •11.2.6 Flush broadcast
- •11.3 Token queue management
- •11.3.1 Queue implementation
- •11.3.2 Queue modification
- •11.3.3 Queue flushing
- •11.4 Token queues
- •11.4.1 Instruction queue
- •11.4.2 Length queue
- •11.4.3 Accept queue
- •11.4.4 Cancel queue
- •11.4.5 Finish queue
- •11.5 Data transfer
- •11.5.1 Loads
- •11.5.2 Stores
- •11.6 Operations
- •11.6.1 Normal operation
- •11.6.2 Cancel operations
- •11.6.3 Bounce operations
- •11.6.4 Flush operations
- •11.6.5 Retirement operations
- •11.7 Multiple coprocessors
- •11.7.1 Interconnect considerations
- •11.7.2 Coprocessor selection
- •11.7.3 Coprocessor switching
- •Vectored Interrupt Controller Port
- •12.1 About the PL192 Vectored Interrupt Controller
- •12.2 About the processor VIC port
- •12.2.1 Synchronization of the VIC port signals
- •12.2.2 Interrupt handler exit
- •12.3 Timing of the VIC port
- •12.3.1 PL192 VIC timing
- •12.3.2 Core timing
- •12.4 Interrupt entry flowchart
- •Debug
- •13.1 Debug systems
- •13.1.1 The debug host
- •13.1.2 The protocol converter
- •13.1.3 The processor
- •13.2 About the debug unit
- •13.2.3 Secure Monitor mode and debug
- •13.2.4 Virtual addresses and debug
- •13.2.5 Programming the debug unit
- •13.3 Debug registers
- •13.3.1 Accessing debug registers
- •13.3.2 CP14 c0, Debug ID Register (DIDR)
- •13.3.3 CP14 c1, Debug Status and Control Register (DSCR)
- •13.3.4 CP14 c5, Data Transfer Registers (DTR)
- •13.3.5 CP14 c6, Watchpoint Fault Address Register (WFAR)
- •13.3.6 CP14 c7, Vector Catch Register (VCR)
- •13.3.10 CP14 c112-c113, Watchpoint Control Registers (WCR)
- •13.3.11 CP14 c10, Debug State Cache Control Register
- •13.3.12 CP14 c11, Debug State MMU Control Register
- •13.4 CP14 registers reset
- •13.5 CP14 debug instructions
- •13.5.1 Executing CP14 debug instructions
- •13.6 External debug interface
- •13.7 Changing the debug enable signals
- •13.8 Debug events
- •13.8.1 Software debug event
- •13.8.2 External debug request signal
- •13.8.3 Halt DBGTAP instruction
- •13.8.4 Behavior of the processor on debug events
- •13.8.5 Effect of a debug event on CP15 registers
- •13.9 Debug exception
- •13.10 Debug state
- •13.10.1 Behavior of the PC in Debug state
- •13.10.2 Interrupts
- •13.10.3 Exceptions
- •13.11 Debug communications channel
- •13.12 Debugging in a cached system
- •13.12.1 Data cache writes
- •13.13 Debugging in a system with TLBs
- •13.14 Monitor debug-mode debugging
- •13.14.1 Entering the debug monitor target
- •13.14.2 Setting breakpoints, watchpoints, and vector catch debug events
- •13.14.3 Setting software breakpoint debug events (BKPT)
- •13.14.4 Using the debug communications channel
- •13.15 Halting debug-mode debugging
- •13.15.1 Entering Debug state
- •13.15.2 Exiting Debug state
- •13.15.3 Programming debug events
- •13.16 External signals
- •Debug Test Access Port
- •14.1 Debug Test Access Port and Debug state
- •14.2 Synchronizing RealView ICE
- •14.3 Entering Debug state
- •14.4 Exiting Debug state
- •14.5 The DBGTAP port and debug registers
- •14.6 Debug registers
- •14.6.1 Bypass register
- •14.6.2 Device ID code register
- •14.6.3 Instruction register
- •14.6.4 Scan chain select register (SCREG)
- •14.6.5 Scan chains
- •14.6.6 Reset
- •14.7 Using the Debug Test Access Port
- •14.7.1 Entering and leaving Debug state
- •14.7.2 Executing instructions in Debug state
- •14.7.3 Using the ITRsel IR instruction
- •14.7.4 Transferring data between the host and the core
- •14.7.5 Using the debug communications channel
- •14.7.6 Target to host debug communications channel sequence
- •14.7.7 Host to target debug communications channel
- •14.7.8 Transferring data in Debug state
- •14.7.9 Example sequences
- •14.8 Debug sequences
- •14.8.1 Debug macros
- •14.8.2 General setup
- •14.8.3 Forcing the processor to halt
- •14.8.4 Entering Debug state
- •14.8.5 Leaving Debug state
- •14.8.8 Reading the CPSR/SPSR
- •14.8.9 Writing the CPSR/SPSR
- •14.8.10 Reading the PC
- •14.8.11 Writing the PC
- •14.8.12 General notes about reading and writing memory
- •14.8.13 Reading memory as words
- •14.8.14 Writing memory as words
- •14.8.15 Reading memory as halfwords or bytes
- •14.8.16 Writing memory as halfwords/bytes
- •14.8.17 Coprocessor register reads and writes
- •14.8.18 Reading coprocessor registers
- •14.8.19 Writing coprocessor registers
- •14.9 Programming debug events
- •14.9.1 Reading registers using scan chain 7
- •14.9.2 Writing registers using scan chain 7
- •14.9.3 Setting breakpoints, watchpoints and vector traps
- •14.9.4 Setting software breakpoints
- •14.10 Monitor debug-mode debugging
- •14.10.1 Receiving data from the core
- •14.10.2 Sending data to the core
- •Trace Interface Port
- •15.1 About the ETM interface
- •15.1.1 Instruction interface
- •15.1.2 Secure control bus
- •15.1.3 Data address interface
- •15.1.4 Data value interface
- •15.1.5 Pipeline advance interface
- •15.1.6 Coprocessor interface
- •15.1.7 Other connections to the core
- •Cycle Timings and Interlock Behavior
- •16.1 About cycle timings and interlock behavior
- •16.1.1 Changes in instruction flow overview
- •16.1.2 Instruction execution overview
- •16.1.3 Conditional instructions
- •16.1.4 Opposite condition code checks
- •16.1.5 Definition of terms
- •16.2 Register interlock examples
- •16.3 Data processing instructions
- •16.3.1 Cycle counts if destination is not PC
- •16.3.2 Cycle counts if destination is the PC
- •16.3.3 Example interlocks
- •16.4 QADD, QDADD, QSUB, and QDSUB instructions
- •16.6 ARMv6 Sum of Absolute Differences (SAD)
- •16.6.1 Example interlocks
- •16.7 Multiplies
- •16.8 Branches
- •16.9 Processor state updating instructions
- •16.10 Single load and store instructions
- •16.10.1 Base register update
- •16.11 Load and Store Double instructions
- •16.12 Load and Store Multiple Instructions
- •16.12.1 Load and Store Multiples, other than load multiples including the PC
- •16.12.2 Load Multiples, where the PC is in the register list
- •16.12.3 Example Interlocks
- •16.13 RFE and SRS instructions
- •16.14 Synchronization instructions
- •16.15 Coprocessor instructions
- •16.16 SVC, SMC, BKPT, Undefined, and Prefetch Aborted instructions
- •16.17 No operation
- •16.18 Thumb instructions
- •AC Characteristics
- •17.1 Processor timing diagrams
- •17.2 Processor timing parameters
- •Signal Descriptions
- •A.1 Global signals
- •A.2 Static configuration signals
- •A.3 TrustZone internal signals
- •A.4 Interrupt signals, including VIC interface
- •A.5 AXI interface signals
- •A.5.1 Instruction read port signals
- •A.5.2 Data port signals
- •A.5.3 Peripheral port signals
- •A.5.4 DMA port signals
- •A.6 Coprocessor interface signals
- •A.7 Debug interface signals, including JTAG
- •A.8 ETM interface signals
- •A.9 Test signals
- •B.1 About the differences between the ARM1136J-S and ARM1176JZ-S processors
- •B.2 Summary of differences
- •B.2.1 TrustZone
- •B.2.2 ARMv6k extensions support
- •B.2.3 Power management
- •B.2.4 SmartCache
- •B.2.7 Tightly-Coupled Memories
- •B.2.8 Fault Address Register
- •B.2.9 Fault Status Register
- •B.2.10 Prefetch Unit
- •B.2.11 System control coprocessor operations
- •B.2.13 Debug
- •B.2.14 Level two interface
- •B.2.15 Memory BIST
- •Revisions
- •Glossary
Summary of ARM1136J-S and ARM1176JZ-S Processor Differences
B.2 Summary of differences
The main differences between the ARM1136J-S and ARM1176JZ-S processors are:
•TrustZone
•Power management on page B-4
•SmartCache on page B-5
•CPU ID on page B-5
•Block transfer operations on page B-5
•Tightly-Coupled Memories on page B-6
•Fault Address Register on page B-6
•Prefetch Unit on page B-7
•System control coprocessor operations on page B-7
•DMA on page B-8
•Debug on page B-9
•Level two interface on page B-9
•Memory BIST on page B-10.
B.2.1 TrustZone
The ARM1176JZ-S processor fully implements the TrustZone architecture for OS security enhancements. This leads to numerous differences between ARM1136J-S and ARM1176JZ-S processors in the core and the Level 1 Memory System, see also Debug on page B-9. The ARM1176JZ-S processor embodies, for TrustZone:
•operation in Secure or Non-secure states
•a new exception model
•a new mode, Secure Monitor mode
•a new instruction, SMC, to switch to Secure Monitor mode
•new CP15 registers to support the TrustZone architecture
•some CP15 registers that are:
—only accessible in Secure Privileged mode
—duplicated, banked, between Secure and Non-secure worlds
•a Level 1 Memory System that supports the Secure and Non-secure memory accesses
•a new NS attribute in the Level 1 page table descriptors to indicate if the targeted memory is Secure or Non-secure.
•VA to PA operations
In addition:
•In the ARM1176JZ-S processor, in Non-secure state, the PLD instruction has no effect on the memory system so it behaves like a NOP. In Secure state, this instruction behaves as a cache preload instruction as implemented in ARM1136J-S processor.
•The ARM1136J-S CP15 c15 Cache Debug Control Register is the Cache Behavior Override Register in the ARM1176JZ-S processor and is architectural with:
—Opcode_1=0
—Crn=9
—Crm=8
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Summary of ARM1136J-S and ARM1176JZ-S Processor Differences
—Opcode_2=0.
B.2.2 ARMv6k extensions support
The ARM1176JZ-S processor adds extra support for the ARMv6k extensions that are not present in the ARM1136JF-S r0p2 processor.
Note
These extensions are present in the ARM1136JF-S r1p0 processor though.
This includes:
•New Store and Load Exclusive instructions for bytes, halfwords and doublewords and a new Clear Exclusive instruction.
•A new true no-operation instruction and yield instruction.
•Architectural remap registers. The memory remap registers in the ARM1136J-S processor are replaced by registers in CP15 c10 in the ARM1176JZ-S processor.
•Cache size restriction through CP15 c1. Cache size can be restricted to 16KB for OSs that do not support page coloring.
•Revised use of TEX bits.
•Revised use of AP bits.
Behavior of TEX bits
The ARMv6 MMU page table descriptors use a large number of bits to describe all of the options for inner and outer cachability. In reality, it is believed that no application requires all of these options simultaneously. Therefore, it is possible to configure the ARM1176JZ-S processor to support only a small number of options by means of the TEX remap mechanism. This implies a level of indirection in the page table mappings.
Recent cores, that include ARM1136J-S processors support this mapping with the MMU remap capability, that was originally designed for debug of the hardware, in CP15 register 15.
By moving one entry in the ARM1176JZ-S processor TEX CB encoding table, with an alias for compatibility, TEX[2:1] is freed for use as two OS managed page table bits. Because binary compatibility is important with existing ARMv6 ports of OSs, this change consists of a separate mode of operation of the MMU. This is called the TEX remap configuration and is controlled by bit [28] TR in CP15 Register 1. The MMU remap registers, other than the Peripheral Remap Register, become architectural and move from CP15 register 15 to CP15 register 10.
Access permissions
In the ARM1176JZ-S processor the APX and AP[1:0] encoding b111 becomes Privileged or User mode read only access. This releases AP[0] to indicate a new abort type, Access Bit fault, when CP15 c1[29] is 1. In theARM1136J-S the encoding b111 was reserved.
B.2.3 Power management
The differences in power management between the ARM1136J-S and ARM1176JZ-S processors are described in:
•Intelligent Energy Management on page B-5.
ARM DDI 0333H |
Copyright © 2004-2009 ARM Limited. All rights reserved. |
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Summary of ARM1136J-S and ARM1176JZ-S Processor Differences
Intelligent Energy Management
The ARM1136J-S processor provides partial support for Dormant mode. The ARM1176JZ-S processor extends this functionality and provides optional support for IEM and Dormant mode.
For Dormant mode the ARM1176JZ-S processor provides the option to instantiate a placeholder that contains all the necessary input clamps to RAM blocks.
The ARM1176JZ-S RTL hierarchy is separated into three blocks to support three different power domains:
•all the RAMs
•the core logic, clocked by CLKIN and FREECLKIN
•four optional IEM Register Slices.
The register slices can provide an asynchronous interface between:
•the Level 2 ports, powered by VCore and clocked by CLKIN
•the AXI system, powered by VSoc and clocked by ACLK signals, one clock for each port.
Level shifters and clamps must be instantiated between power domains.ARM1176JZ-S processors do not implement the asynchronous interface present in the ARM1136J-S processor and, if implemented, you can use the IEM Register Slices to provide the asynchronous interface in the Level 2 ports of the ARM1136J-S processor.
B.2.4 SmartCache |
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Unlike ARM1136J-S processors, the ARM1176JZ-S processor does not implement the |
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SmartCache feature for the Tightly-Coupled Memories. As a consequence, the TCMs in |
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ARM1176JZ-S processors always behave as local RAMs and the SC bit, bit [1], of each TCM |
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Region Register is Read As Zero and Ignored on writes. The SmartCache dedicated valid and |
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dirty RAMs are not implemented in the ARM1176JZ-S processor. |
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The ARM1176JZ-S processor does not include these RAMs: |
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ITCValidRAM |
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DTCValidRAM |
• |
DTCDirtyRAM. |
B.2.5 |
CPU ID |
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The ARM1176JZ-S processor implements the revised ARMv7 CPU ID scheme using CP15 c0. |
B.2.6 |
Block transfer operations |
Unlike ARM1136J-S processors, the ARM1176JZ-S processor does not implement some block transfer operations and these operations are Undefined in ARM1176JZ-S processors:
•Prefetch Range operations, Instruction and Data
•Stop Prefetch Range operations
•Read Block Transfer Status Register operations.
The ARM1176JZ-S processor implements all the other block transfer operations:
•Invalidate Cache Range, Instruction and Data
•Clean Data Cache Range
•Clean and Invalidate Data Cache Range.
ARM DDI 0333H |
Copyright © 2004-2009 ARM Limited. All rights reserved. |
B-5 |
ID012410 |
Non-Confidential, Unrestricted Access |
|
Summary of ARM1136J-S and ARM1176JZ-S Processor Differences
B.2.7 Tightly-Coupled Memories
The ARM1136J-S processor implements zero or one Tightly Coupled Memories on each side, Instruction and Data. The possible TCM sizes for ARM1136J-S for each side are:
•0KB
•4KB
•8KB
•16KB
•32KB
•64KB.
The ARM1176JZ-S processor implements zero, one or two Tightly Coupled Memories on each side. For each side, the two TCMs are physically located within one RAM. Table B-1 lists the possible configurations for ARM1176JZ-S Tightly-Coupled Memories for each side:
Table B-1 TCM for ARM1176JZ-S processors
Number of TCM |
TCM size |
RAM size |
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0 |
0 KB |
0 KB |
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1 |
4 KB |
4 KB |
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2 |
4 KB |
8 KB |
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2 |
8 KB |
16 KB |
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2 |
16 KB |
32 KB |
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2 |
32 KB |
64 KB |
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B.2.8 Fault Address Register
ARM1136J-S processors includes an Instruction Fault Address Register in the system control coprocessor, CP15, with the encoding:
•Opcode_1 = 0
•Crn = 6
•Crm = 0
•Opcode_2 = 1.
The ARM1136J-S IFAR is only updated on watchpoints.
The ARM1136J-S IFAR is the Watchpoint Fault Address Register in ARM1176JZ-S processors. The WFAR is in the CP14 coprocessor with the encoding:
•Opcode_1 = 0
•Crn = 0
•Crm = 6
•Opcode_2 = 0.
The CP15 access to this register is deprecated and only possible in Secure Privileged modes.
The ARM1176JZ-S processor introduces a new Instruction Fault Address Register in the system control coprocessor with the encoding:
•Opcode_1 = 0
•Crn = 6
•Crm = 0
•Opcode_2 = 2.
ARM DDI 0333H |
Copyright © 2004-2009 ARM Limited. All rights reserved. |
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